Image forming material

ABSTRACT

The present invention relates to an image forming material having, on a substrate, an image forming layer that includes at least (A) a novolac type phenolic resin containing phenol as a structural unit, (B) a photo-thermal converting agent, and (C) a specific ammonium compound or a specific onium salt.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 USC 119 from Japanese patentApplication Nos. 2003-15905 and 2003-24499, the disclosures of which areincorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image forming material, and, moreparticularly, to a positive image forming material useful as a positiveplanographic printing plate precursor suitable for a so-called “directplate-making” by an infrared laser, by which direct plate-making a platecan be made directly from a digital signal in particular such as from acomputer.

2. Description of the Related Art

In recent years, laser technology has rapidly progressed; in particular,higher output and smaller size solid lasers and semiconductor lasersthat have an emission region from near infrared to infrared are readilyavailable. These lasers are very useful as an exposure light source whena planographic plate is directly made from digital data such as fromcomputers.

A known positive photosensitive image forming material for use in adirect plate-making by an infrared laser includes a novolac resin or thelike as a resin soluble in an aqueous alkali solution. For example, apositive photosensitive image forming material is known which includes aresin that has a phenolic hydroxyl group and is soluble in an aqueousalkali solution such as a novolac resin, a substance that absorbs lightto generate heat, and a positive photosensitive compound such as anonium salts, quinone diazide compounds are added (Japanese PatentApplication Laid-open (JP-A) No. 7-285275). In the above positivephotosensitive image forming material, the positive photosensitivecompound, in an image portion, works as a dissolution inhibitor thatsubstantially decreases the solubility of the resin soluble in anaqueous alkali solution. Meanwhile, in a non-image portion, owing toheat, the positive photosensitive compound does not exhibit thedissolution inhibiting effect and the resin soluble in an aqueous alkalisolution can be removed by development. In this way, an image is formed.

Furthermore, a positive photosensitive image forming material isdisclosed (International Publication WO97/39894 and European PatentApplication Laid-open (EP-A) No. 0,823,327). This positivephotosensitive image forming material includes a substance that absorbslight to generate heat and a resin whose solubility in an aqueous alkalisolution is changed by heat. In this positive photosensitive imageforming material, an image portion has low solubility in an aqueousalkali solution, and a solubility of a non-image portion in an aqueousalkali solution is increased by heat. In this way, the non-image portionbecomes able to be removed by development to form an image.

In a conventional planographic printing plate precursor, a novolac resinis preferably used since the novolac resin interacts strongly with adissolution inhibitor, the difference in solubility between the novolacresin in an exposed region and the novolac resin in a non-exposed regionis large, and the novolac resin has excellent ink-receiving property. Anovolac resin is used also in a positive photosensitive image formingmaterial suitable for infrared laser exposure, for similar reasons. Asthe novolac resin, in particular, novolac resins obtained bypolymerizing phenols such as phenol, cresol, and xylenol withformaldehyde under acidic condition are generally used.

As the dissolution inhibitor, although a variety of compounds are understudy, it is known that in particular onium salt type dissolutioninhibitors exhibit very strong dissolution inhibiting effect. However,when a general onium salt compound is added, although an improvement inthe alkali-resistance in a non-exposed portion can be achieved owing tothe strong dissolution inhibiting effect of the onium salt, there existsa problem that the sensitivity is lowered. In order to overcome thisproblem, a novel photosensitive material that uses a specific onium saltis disclosed. For instance, onium salts disclosed in JP-A No.2002-278050 and quaternary ammonium salts disclosed in JP-A No.2003-107688 are known to have excellent characteristics in which highdissolution inhibiting power and high sensitivity are compatible.

However, it has become apparent that there is a problem that as timepasses after the exposure, developability of a photosensitive materialthat uses the above onium-salt type dissolution inhibitor declines anddevelopment failure is caused. Such decline in the developability withtime lapse after the exposure is problematic in a plate making processand an improvement in the stability of the developability is required.(Hereinafter, the magnitude of developability change after the exposureis expressed by the storability after exposure, and larger decrease indevelopability is referred to as “worse storability after exposure”.)

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide an image formingmaterial that can be used for a heat-example type positive planographicprinting plate precursor, is excellent in the difference (solubilitydiscrimination) in the solubility in a developer between an exposedportion and a non-exposed portion, and has small degree of change of thedevelopability with time after the exposure (excellent in thestorability after the exposure).

The present inventors found that when a combination of a novolac-typephenolic resin containing phenol as a structural unit and a specificammonium compound or a specific onium salt is contained in an imageforming layer, the storability after the exposure can be largelyimproved without decline in the sensitivity and in the developmentlatitude. Thereby, the invention has been accomplished.

A first image forming material according to the present inventioncomprises, on a substrate, an image forming layer that contains at least(A) a novolac type phenolic resin that contains phenol as a structuralunit (hereinafter appropriately referred to as “particular novolacresin”), (B) a photo-thermal converting agent, and (C) a compoundrepresented by the following general formula (1-1) (hereinafterappropriately referred to as “particular ammonium compound”).

In the general formula (1-1), R¹ represents a residue that forms a ringstructure containing a N¹ atom. R² and R³ each independently representan organic group and may combine with each other to form a ringstructure. Furthermore, at least one of R² and R³ may combine with R¹ toform a ring structure. X⁻ represents a conjugate base of an organic acidor inorganic acid.

Furthermore, a second image forming material according to the inventioncomprises, on a substrate, an image forming layer that contains at least(A) a novolac type phenolic resin that contains phenol as a structuralunit (the particular novolac resin), (B) a photo-thermal convertingagent, and (C) an onium salt represented by the following generalformula (1-2) (hereinafter appropriately referred to as “particularonium salt”).X⁻M⁺  General formula (1-2)

(In the general formula (1-2), X⁻ represents an anion having at leastone substituent group having an alkali dissociative proton. M⁺represents a counter cation selected from sulfonium, iodonium, ammonium,phosphonium and oxonium.)

In general, when the development latitude is sacrificed, the storabilityafter the exposure can be secured. However, surprisingly, in theinvention, by adopting the above constitution, in addition to makingboth the sensitivity and the development latitude compatible,improvement in the storability after the exposure becomes also possible.

In the invention, “heat-example type” means that an image formingmaterial can be recorded by the heat-example exposure.

The definition of the heat-example exposure in the invention will bedetailed. As described in Hans-Joachim Timpe, IS & Ts NIP 15:1999International Conference on Digital Printing Technologies, p 209, it isknown that there are two examples, when largely divided, in a processfrom photo-excitation to chemical or physical change of a lightabsorbing substance when the light absorbing substance (for instancedye) in a photosensitive material is excited by light and forms an imagethrough the chemical or physical change. One example is a so-calledphoton-example in which an optically excited light absorbing substanceundergoes a certain photochemical interaction (for instance, energytransfer, electron transfer) with another reactive substance in thephotosensitive material and is deactivated, then the resultant activatedreactive substance causes the chemical or physical change necessary forthe image formation. The other example is a so-called heat-example inwhich an optically excited light absorbing substance generates heat andis deactivated, and by utilizing the generated heat, a reactivesubstance causes the chemical or physical change necessary for the imageformation. Other than the above-mentioned examples, there are specialexamples such as an ablation process in which a substance explosivelyscatters owing to a locally concentrated light energy and a multi-photonabsorption process in which one molecule absorbs a lot of photons at onetime. However, these special examples are omitted herein.

Exposure processes that make use of the above respective examples arecalled a photon-example exposure and a heat-example exposure. Thetechnical difference between the photon-example exposure and theheat-example exposure exists in whether or not energy amounts of severalphotons can be summed up for providing the energy required for a targetreaction. For instance, a case is supposed where a certain reaction iscaused by n photons. In the photon-example exposure, since aphotochemical interaction is utilized, energy amounts of respectivephotons cannot be summed up due to the requirement of energyconservation law of quantum and momentum conservation law of quantum.That is, in order to cause a certain reaction, it is necessary tosatisfy the relation: “amount of energy of single photon≧amount ofenergy of reaction”. On the other hand, in the heat-example exposure,since heat is generated after the photo-excitation, that is, since theoptical energy is converted to heat and utilized, energy amounts ofphotons can summed up. Accordingly, in order to cause the reaction, itis sufficient to satisfy the relation: “amount of energy of nphotons≧amount of energy of reaction”. However, the summation of amountsof energy is restricted by the heat diffusion. That is, if a subsequentphotoexcitation-deactivation process is caused and heat is generatedbefore heat diffuses from a given exposure portion (reaction point)according to the thermal diffusion, heat is certainly accumulated and atemperature in this portion rises. However, when subsequent heatgeneration is delayed, the heat diffuses and is not accumulated. Thatis, in the heat-example exposure, even when the total exposure energy isthe same, the results are different between a case where light havinghigh energy amount is irradiated for a short period and a case wherelight having low energy amount is irradiated for a long period. Andshorter irradiation is advantageous to the accumulation of heat.

Of course, in some cases, a similar phenomenon may occur even in thephoton-example exposure owing to an influence of the diffusion of asubsequent reaction species. However, in principle, such a phenomenondoes not occur.

That is, when this phenomenon is expressed as the characteristics of thephotosensitive material, while, in the photon-example, a ratio of thespecific sensitivity of the photosensitive material (an energy amountfor a reaction necessary for forming an image) to an exposure powerdensity (W/cm²) (=energy density per unit time period) is constantregardless of the exposure power density, in the heat-example, a ratioof the specific sensitivity of the photosensitive material to theexposure power density increases as the exposure power densityincreases. Accordingly, in the case where an exposure time is fixed tosuch a period that the productivity practically required for an imagerecording material can be maintained, and the respective examples arecompared, in the case of the photon-example exposure, high sensitivitysuch as substantially 0.1 mJ/cm² can be ordinarily achieved. However,since a very slight amount of exposure can cause the reaction, theretends to occur a problem that low exposure fog is caused in an unexposedportion. On the other hand, in the case of the heat-example exposure,although a reaction is caused only when the energy amount of theexposure exceeds a certain value, usually about 50 mJ/cm² from theviewpoint of the thermal stability of the photosensitive material.Accordingly, the problem of the low exposure fog can be avoided in thecase of the heat-example exposure.

Practically, in the heat-example exposure, the exposure power density ona plate surface of the photosensitive material has to be no less than5000 W/cm², preferably of 10000 W/cm². However, though not detailedhere, when a high power density laser of 5.0×10⁵ W/cm² or higher isused, the ablation is caused, resulting in a problem that unfavorablecontamination of a light source is caused.

DETAILED DESCRIPTION OF THE INVENTION

In the following, the present invention will be detailed.

One embodiment of the present invention is an image forming material(S1) comprising, on a substrate, an image forming layer which includesat least (A) a novolac type phenolic resin containing phenol as astructural unit, (B) a photo-thermal converting agent, and (C) acompound represented by the following general formula (1-1):

wherein in the general formula (1-1), R¹ represents a residue which,together with N¹, forms a ring structure; R² and R³ each independentlyrepresent an organic group and may combine with each other to form aring structure; at least one of R² and R³ may combine with R¹ to form aring structure; and X⁻ represents a conjugate base of an organic acid oran inorganic acid.

Another embodiment of the invention is the image forming material (S1),wherein the compound represented by the general formula (1-1) isrepresented by the following general formula (1-1-a):

wherein in the general formula (1-1-a), R² and R³ each independentlyrepresent an organic group and may combine with each other to form aring structure; X⁻ represents a conjugate base of an organic acid or aninorganic acid; R⁴ through R⁷ each independently represent a hydrogenatom or a substituent, may be the same as or different from one another,and may combine with one another to form a ring; R⁴ through R⁷ may eachcombine with L¹, R² or R³ to form a ring structure; when a bond betweenL¹ and C¹ or C² is a double bond or a triple bond, some of R⁴ through R⁷do/does not exist in accordance with the existence of the double bond orthe triple bond; L¹ represents a single bond or a divalent linkage groupwhich, together with —C¹—N¹—C²—, forms a ring structure; R⁴ and R⁵ mayrepresent an identical atom or an identical substituent so that a bondbetween C¹ and R⁴, which is also R⁵, becomes a double bond; and R⁶ andR⁷ may represent an identical atom or an identical substituent so that abond between C² and R⁶, which is also R⁷, becomes a double bond.

Another embodiment of the invention is the image forming material (S1),wherein a mass of the compound represented by the general formula (1-1)is 50% or less of a mass of a total solids content in the image forminglayer.

Another embodiment of the invention is the image forming material (S1),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the followinggeneral formula (I), and an aldehyde:

wherein in the general formula (I), R¹ and R² each independentlyrepresent a hydrogen atom, an alkyl group, or a halogen atom.

Another embodiment of the invention is the image forming material (S1),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the generalformula (I), and an aldehyde, and a phenol content in monomers thatconstitute the novolac type phenolic resin is from 21 to 90% by mole.

Another embodiment of the invention is the image forming material (S1),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the generalformula (I), and an aldehyde, and a weight average molecular weight ofthe novolac type phenolic resin is from 500 to 50000.

Another embodiment of the invention is the image forming material (S1),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the generalformula (I), and an aldehyde, and a proportion of the novolac typephenolic resin to a total solids content in the image forming layer isfrom 0.1 to 20% by mass.

Another embodiment of the invention is an image forming material (S2)comprising, on a substrate, an image forming layer which includes atleast (A) a novolac type phenolic resin containing phenol as astructural unit, (B) a photo-thermal converting agent, and (C) an oniumsalt represented by the following general formula (1-2):X⁻M⁺  General formula (1-2)

wherein, in the general formula (1-2), X⁻ represents an anion includingat least one substituent that has an alkali dissociative proton and M⁺represents a counter cation selected from the group consisting of asulfonium ion, an iodonium ion, an ammonium ion, a phosphonium ion, andan oxonium ion.

Another embodiment of the invention is the image formation material(S2), wherein M⁺ in general formula (1-2) is represented by thefollowing general formula (M-1)

wherein in the general formula (M-1), R¹ represents a residue which,together with N¹, forms a ring structure; R² and R³ each independentlyrepresent an organic group and may combine with each other to form aring structure; and at least one of R² and R³ may combine with R¹ toform a ring structure.

Another embodiment of the invention is the image forming material (S2),wherein a mass of the compound represented by general formula (1-2) is50% or less of a mass of a total solids content in the image forminglayer.

Another embodiment of the invention is the image forming material (S2),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the followinggeneral formula (I), and an aldehyde:

wherein in the general formula (I), R¹ and R² each independentlyrepresent a hydrogen atom, an alkyl group, or a halogen atom.

Another embodiment of the invention is the image forming material (S2),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the generalformula (I), and an aldehyde, and a phenol content in monomers thatconstitute the novolac type phenolic resin is from 21 to 90% by mole.

Another embodiment of the invention is the image forming material (S2),wherein the novolac type phenolic resin is a resin obtained bycondensing phenol, a substituted phenol represented by the generalformula (I), and an aldehyde, and a weight average molecular weight ofthe novolac type phenolic resin is from 500 to 50000.

Still another embodiment of the present invention is the image formingmaterial (S2), wherein the novolac type phenolic resin is a resinobtained by condensing phenol, a substituted phenol represented by thegeneral formula (I), and an aldehyde, and a proportion of the novolactype phenolic resin to a total solids content in the image forming layeris from 0.1 to 20% by mass.

A first image forming material according to the invention is constitutedby having, on a substrate, an image forming layer that includes at least(A) a novolac type phenolic resin having phenol as a structural unit,(B) a photo-thermal converting agent, and (C) a compound expressed bythe above formula (1-1). A second image forming material according tothe invention is constituted by having, on a substrate, an image forminglayer that includes at least (A) a novolac type phenolic resin havingphenol as a structural unit, (B) a photo-thermal converting agent, and(C) an onium salt expressed by the general formula (1-2). In thefollowing, the respective components in the image forming layeraccording to the invention will be explained sequentially.

((A) Novolac Type Phenolic Resin Containing Phenol as Structural Unit)

An image forming layer according to the invention includes a novolactype phenolic resin that contains phenol as a structural unit(particular novolac resin). The particular novolac resin is notparticularly restricted as far as phenol is contained as a structuralunit in a molecule. Phenol as the structural unit preferably occupies 20to 90 mole %, more preferably from 31 to 85 mole %, and most preferablyfrom 51 to 80 mole % of the structural units that constitutes thenovolac resin.

Such particular novolac resin may be preferably (A-1) a resin that areobtained by condensing phenol, a substituted phenol represented by thefollowing general formula (I), and an aldehyde. The particular novolacresin may be more preferably (A-2) a resin obtained by condensingphenol, a phenol derivative selected from cresol and xylenol, and analdehyde. Here, plural kinds of the substituted phenols may be containedin the particular novolac resin.

((A-1) Resin Obtained by Condensing Phenol, a Substituted PhenolRepresented by the Following General Formula (I), and an Aldehyde)

First, a resin obtained by condensing phenol, a substituted phenolrepresented by the following general formula (I), and an aldehyde(hereinafter occasionally referred to as “(A-1) resin”) will bedetailed.

In the general formula (I), R¹ and R² each independently represent ahydrogen atom, an alkyl group or a halogen atom. As the alkyl group, analkyl group having 1 to 3 carbon atoms is preferable, and an alkyl grouphaving 1 or 2 carbon atoms is more preferable. The halogen atom may be afluorine atom, a chlorine atom, a bromine atom, or an iodine atom, andpreferably a chlorine atom or a bromine atom. R³ represents an alkylgroup having 3 to 6 carbon atoms or a cycloalkyl group having 3 to 6carbon atoms.

Examples of the substituted phenol represented by the general formula(I) that is used as a component of the (A-1) resin includeisopropylphenol, t-butylphenol, t-amylphenol, hexylphenol,cyclohexylphenol, 3-methyl-4-chloro-6-t-butylphenol, isopropylcresol,t-butylcresol, t-amylcresol. Among these substituted phenols,t-butylphenol and t-butylcresol are preferable.

Examples of the aldehyde that is used in the (A-1) resin includealiphatic and aromatic aldehydes such as formaldehyde, acetaldehyde,acrolein, crotonaldehyde. Among these aldehydes, formaldehyde andacetaldehyde can be preferably used.

A phenol content in a monomer in the (A-1) resin is preferably in therange of from 21 to 90 mole %, more preferably from 31 to 85 mole %, andmost preferably from 51 to 80 mole %.

The weight average molecular weight of the (A-1) resin is preferably inthe range of from 500 to 50000, more preferably from 700 to 20000, andparticularly preferably from 1000 to 10000.

A ratio of the (A-1) resin to the whole solids content in the imageforming layer according to the invention is preferably in the range offrom 0.1 to 20% by mass, more preferably from 0.2 to 10% by mass, andparticularly preferably from 0.2 to 5% by mass. In the case where theratio is smaller than 0.1% by mass, the effect of the addition becomesinsufficient, while in the case where the ratio is larger than 20% bymass, the sensitivity tends to decline.

((A-2) Resin Obtained by Condensing Phenol, a Phenol Derivative Selectedfrom Cresol and Xylenol, and an Aldehyde)

Next, the (A-2) resin obtained by condensing phenol, a phenol derivativeselected from cresol and xylenol, and an aldehyde (hereinafteroccasionally referred to as “(A-2) resin”) will be detailed.

As the aldehyde that is used in the condensation reaction for obtainingthe (A-2) resin, aldehydes that are cited in the foregoing explanationof (A-1) resin can be cited.

The (A-2) resin that is used in the invention is preferably a novolacresin such as a phenol formaldehyde resin or a phenol/cresol (all of m-,p-, and m-/p-mixture are usable) mixture formaldehyde resin.

A phenol content in a monomer in the (A-2) resin is preferably in therange of from 21 to 90 mole %, more preferably from 31 to 85 mole %, andparticularly preferably from 51 to 80 mole %. The monomers in the (A-2)resin preferably includes m-cresol in an amount of 10 mole % or more.

The weight average molecular weight of the (A-2) resin is preferably inthe range of from 500 to 50000, more preferably from 700 to 20000, andparticularly preferably from 1000 to 10000. The number average molecularweight of the (A-2) resin is preferably 500 or more and more preferablyin the range of from 750 to 650,000. The dispersion (weight averagemolecular weight/number average molecular weight) of the (A-2) resin ispreferably in the range of from 1.1 to 10.

The content of the (A-2) resin that is used in the invention ispreferably in the range of from 10 to 95% by mass, and more preferablyfrom 20 to 90% by mass based on the whole solids content in the imagerecording layer of the image forming material. In the case where thecontent is less than 10% by mass, in some cases, the improvement effectof the press life due to the baking is so low that the resultantprinting plate cannot be used.

The particular novolac resin such as the (A-1) resin or the (A-2) resinaccording to the invention may be used singly or plural kinds of theparticular novolac resins may be used in combination.

A generally used novolac resin other than the particular novolac resinaccording to the invention may be used in combination with theparticular novolac resin. In that case, the novolac resin other than theparticular novolac resin can be blended in an amount of from 5 to 50% bymass, preferably from 5 to 30% by mass, and particularly preferably from5 to 20% by mass based on the entire amount of the novolac resins.

As a method of producing the particular novolac resins according to theinvention, a method described in Shin Jikken Kagaku Kouza 19, KoubunshiKagaku I, (Maruzen Co., Ltd, 1993): p. 300 can be applied. According tothe method, phenol and a substituted phenol (e.g. a cresol that is citedin the explanation of the (A-1) resin and (A-2) resin) are allowed toreact in a solvent together with an aqueous solution of formaldehyde byusing an acid as a catalyst, whereby phenol, o-site or p-site in thesubstituted phenol component and formaldehyde undergoes dehydrationcondensation to produce the particular novolac resin.

The dehydration condensation between phenol and the o-site or p-site ofthe substituted phenol component and formaldehyde can be performed asfollows. First, a solution containing phenol and the substituted phenolcomponent in an amount of 60 to 90% by mass, and preferably from 70 to80% by mass in terms of the total mass of phenol and the substitutedphenol component. Then, formaldehyde is added to the solution so thatthe molar ratio of the amount of formaldehyde to the total amount ofphenol and the substituted phenol component is in the range of from 0.2to 2.0, preferably from 0.4 to 1.4, and particularly preferably from 0.6to 1.2. Further, an acid catalyst is added to the solution at atemperature of from 10 to 150° C. so that the molar ratio of the amountof the acid catalyst to the total amount of phenol and the substitutedphenol component is in the range of from 0.01 to 0.1, and preferably inthe range of from 0.02 to 0.05. Then, the solution is stirred forseveral hours while the temperature of the solution is kept in theforegoing range, whereby the dehydration condensation is achieved. Thereaction temperature is preferably in the range of from 70 to 150° C.and more preferably from 90 to 140° C.

Solvents usable in the reaction are, for instance, water, acetic acid,methanol, ethanol, 2-propanol, 2-methoxyethanol, ethyl propionate,ethoxyethyl propionate, 4-methyl-2-pentanone, dioxane, xylene, benzeneand the like.

As the acid catalyst, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid,zinc acetate, manganese acetate, cobalt acetate, magnesiummethylsulfonate, aluminum chloride, zinc oxide and the like can becited.

The monomers and dimers remaining in a synthesized phenolic resin aredistilled and removed such that the total concentration of the remainingmonomers and dimers is preferably in the range of from 0.01 to 10% bymass and more preferably in the range of from 0.01 to 2.0% by mass.

Specific examples (S-1 through S-18) of the particular novolac resinthat are preferably used in the invention are as follows.

-   (S-1) Polycondensation product of phenol, m-cresol and p-cresol    (molar ratio 30:50:20, weight average molecular weight 4000)-   (S-2) Polycondensation product of phenol, m-cresol and o-cresol    (molar ratio 50:30:20, weight average molecular weight 5500)-   (S-3) Polycondensation product of phenol, m-cresol and p-cresol    (molar ratio 70:10:20, weight average molecular weight 4500)-   (S-4) Polycondensation product of phenol, m-cresol and p-cresol    (molar ratio 50:30:20, weight average molecular weight 4200)-   (S-5) Polycondensation product of phenol and m-cresol (molar ratio    70:30, weight average molecular weight 4500)-   (S-6) Polycondensation product of phenol and p-cresol (molar ratio    60:40, weight average molecular weight 6000).-   (S-7) Polycondensation product of phenol and o-cresol (molar ratio    50:50, weight average molecular weight 3900)-   (S-8) Polycondensation product of phenol and p-ethyl phenol (molar    ratio 40:60, weight average molecular weight 4000)-   (S-9) Polycondensation product of phenol and p-tertiary butyl phenol    (molar ratio 80:20, weight average molecular weight 5000)-   (S-10) Polycondensation product of phenol and 2,5-xylenol (molar    ratio 90:10, weight average molecular weight 8000)-   (S-11) Polycondensation product of phenol and 2,3-xylenol (molar    ratio 75:25, weight average molecular weight 4400)-   (S-12) Polycondensation product of phenol and 2,4-xylenol (molar    ratio 80:20, weight average molecular weight 5500)-   (S-13) Polycondensation product of phenol and 3,4-xylenol (molar    ratio 70:30, weight average molecular weight 7400)-   (S-14) Polycondensation product of phenol and p-nonyl phenol (molar    ratio 30:70, weight average molecular weight 9800)-   (S-15) Polycondensation product of phenol and p-phenyl phenol (molar    ratio 65:45, weight average molecular weight 4000)-   (S-16) Polycondensation product of phenol and o-phenyl phenol (molar    ratio 50:50, weight average molecular weight 4500)-   (S-17) Polycondensation product of phenol, m-cresol and 2,5-xylenol    (molar ratio 80:15:5, weight average molecular weight 5500)-   (S-18) Polycondensation product of phenol, m-cresol and p-phenyl    phenol (molar ratio 40:10:50, weight average molecular weight 4500)

Among these examples, (S-1) through (S-13) are preferable and (S-1)through (S-8) are particularly preferable.

Since phenol, which is included as the structural unit in the particularnovolac resin according to the invention, has more active sites than thesubstituted phenols, an obtained polymer is likely to form athree-dimensional structure as a whole. Accordingly, it is consideredthat in the heat-example exposure, owing to such three-dimensionalstructure, if interaction of the particular novolac resin with aparticular ammonium compound (inhibitor) or a particular onium salt isonce broken, it is difficult to reestablish the interaction.

It is inferred that because the interaction between an alkali-solubleresin such as a novolac resin and the dissolution inhibitor recoverswith time, the solubility (storability after the exposure) decreaseswith time. On the other hand, in the invention, it is considered thatowing to the use of the particular novolac resin, the recovery of theinteraction between the novolac resin and the particular ammoniumcompound in an exposed portion or between the novolac resin and theparticular onium salt in an exposed portion is effectively disturbed,resulting in exhibition of the effect of the present invention.

In the image forming layer according to the invention, in combinationwith the particular novolac resin, a resin (hereinafter occasionallyreferred to as “other alkali-soluble resin”) which is insoluble in waterand soluble in alkaline water and which is other than the particularnovolac resin can be used in combination with the particular novolacresin. The simultaneous use of the particular novolac resin and suchother alkali-soluble resin is preferable from the viewpoint of expandingthe development latitude.

Such other alkali-soluble resin may be polyhydroxystyrene,polyhalogenated hydroxystyrene, copolymer ofN-(4-hydroxyphenyl)methacrylamide, hydroquinone monomethacrylatecopolymer, the sulfonylimide base polymer described in JP-A No. 7-28244,the carboxyl group containing polymer described in JP-A No. 7-36184, orthe like. Other than the above, acrylic resins each containing aphenolic hydroxyl group described in JP-A No. 51-34711, acrylic resinseach containing a sulfonamide group described in JP-A No. 2-866,urethane base resins, various kinds of alkali-soluble polymer compoundsalso can be used as such other alkali-soluble resins.

These other alkali-soluble resins preferably have weight averagemolecular weights in the range of from 500 to 200,000, and numberaverage molecular weights in the range of from 200 to 60,000.

The above-mentioned other alkali-soluble resin may be used singly ormultiple kinds of such other alkali-soluble resins may be used incombination. Such other alkali-soluble resin(s) can be contained in therecording layer (i.e. image forming layer) in an amount of preferably0.5 to 30% by mass based on the whole solids content of the recordinglayer, and more preferably from 0.5 to 20% by mass based on the wholesolids content of the recording layer.

((C) Compound Represented by General Formula (1-1))

The first image forming layer according to the invention contains acompound (hereinafter, occasionally referred to as “particular ammoniumcompound”) represented by the following general formula (1-1).

In the general formula (1-1), R¹ represents a residue that forms a ringstructure containing a N¹ atom. R² and R³ each independently representan organic group and may combine with each other to form a ringstructure. At least one of R² and R³ may combine with R¹ to form a ringstructure. X⁻ represents a conjugate base of an organic acid or aninorganic acid.

The residue represented by the R¹ may be any organic group as far as itis a divalent organic group that can form a ring structure containing N¹atom. That is, not only a hydrocarbon ring structure, but also a ringstructure containing a plurality of nitrogen atoms or a ring structurecontaining another hetero atom such as an oxygen atom, sulfur atom maybe the ring structure formed by the combination of R¹ and N¹. The ringstructure formed by the combination of R¹ and N¹ may contain a doublebond and the combination of R¹ and N¹ may form a polycyclic structure.

As a preferable example of the ring structure that is formed by R¹ andN¹ atom, a three- to ten-membered ring can be cited. From the viewpointof more efficiently removing the dissolution inhibiting effect, a three-to eight-membered ring is preferable, and when considering thesuitability for synthesis, a five-membered ring and a six-membered ringare preferable.

The ring structure formed by R¹ and N¹ atom may further contain asubstituent, and as such substituent, an alkyl group, an aryl group, ahalogen atom, or the like can be cited.

R² and R³ may be the same as or different from each other and can bearbitrarily selected from organic groups. However, in view of exhibitingan inhibition, that is, a strong dissolution inhibition action, a groupsuch as an alkyl group, an aryl group, a group represented by thefollowing general formula (2-1) and the like are preferable. If both R²and R³ are alkyl groups, the sum of the numbers of carbon atoms thereofhas to be no less than 6. It is preferable that at least one of R² andR³ has a branched structure or a ring structure. In view of theefficiency of removing the dissolution inhibiting effect, it ispreferable that at least one of R² and R³ contains an aromatic ring, andit is more preferable that each of R² and R³ contains an aromatic ring.

In the general formula (2-1), R⁴, R⁵ and R⁶ each independently representan arbitrary possible substituent. R⁴, R⁵ and R⁶ may be the same as ordifferent from each other. Any two of R⁴, R⁵ and R⁶ may combine witheach other to form a ring structure. The bond between C¹ and one of R⁴and R⁵ may be a double bond, and in such a case the other one of R⁴ andR⁵ does not exist. And n represents an integer of 0 or 1 and mrepresents an integer from 0 to 5. When m is larger than 1, a pluralityof R⁶s exist, and in such a case, each R⁶ may be same or different andmay combine with another R⁶ to form a ring structure. In the case wheren is 1, in view of the suitability for synthesis, it is preferable thatat least one of R⁴ and R⁵ is a hydrogen atom, and it is most preferablethat both R⁴ and R⁵ are hydrogen atoms.

As the substituent represented by R² or R³, the following substituentscan be cited as examples:

alkyl groups (each preferably having 1 to 20 carbon atoms, morepreferably 1 to 16 carbon atoms, and particularly preferably 1 to 12carbon atoms; specifically such as a methyl group, an ethyl group, ann-butyl group, an iso-propyl group, a tert-butyl group, an n-octylgroup, an n-decyl group, an n-hexadecyl group, a cyclopropyl group, acyclopentyl group, a cyclohexyl group, and a 2-cyclohexylethyl group),alkenyl groups (each preferably having 2 to 20 carbon atoms, morepreferably 2 to 12 carbon atoms, and particularly preferably 2 to 8carbon atoms; such as a vinyl group, an allyl group, a 2-betenyl group,a 3-pentenyl group, and a 2-cyclohexenylmethyl group), alkynyl groups(each preferably having 2 to 20 carbon atoms, more preferably 2 to 12carbon atoms, and particularly preferably 2 to 8 carbon atoms; such as apropargyl group and a 3-pentynyl group), aryl groups (each preferablyhaving 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, andparticularly preferably 6 to 12 carbon atoms; such as a phenyl group, ap-methyl phenyl group, and a naphthyl group), amino groups (eachpreferably having 0 to 20 carbon atoms, more preferably 0 to 12 carbonatoms, and particularly preferably 0 to 6 carbon atoms; such as an aminogroup, a methylamino group, a dimethylamino group, a diethylamino group,a diphenylamino group, and a dibenzylamino group), alkoxy groups (eachpreferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbonatoms, and particularly preferably 1 to 8 carbon atoms; such as amethoxy group, an ethoxy group, and a butoxy group), aryloxy groups(each preferably having 6 to 20 carbon atoms, more preferably 6 to 16carbon atoms, and particularly preferably 6 to 12 carbon atoms; such asa phenyloxy group and a 2-naphthyloxy group),

acyl groups (each preferably having 1 to 20 carbon atoms, morepreferably 1 to 16 carbon atoms, and particularly preferably 1 to 12carbon atoms; such as an acetyl group, a benzoyl group, a formyl group,and a pivaloyl group), alkoxycarbonyl groups (each preferably having 2to 20 carbon atoms, more preferably 2 to 16 carbon atoms, andparticularly preferably 2 to 12 carbon atoms; such as a methoxycarbonylgroup and an ethoxycarbonyl group), aryloxycarbonyl groups (eachpreferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbonatoms, and particularly preferably 7 to 10 carbon atoms; such as aphenyloxycarbonyl group), acyloxy groups (each preferably having 2 to 20carbon atoms, more preferably 2 to 16 carbon atoms, and particularlypreferably 2 to 10 carbon atoms; such as an acetoxy group and abenzoyloxy group), acylamino groups (each preferably having 2 to 20carbon atoms, more preferably 2 to 16 carbon atoms, and particularlypreferably 2 to 10 carbon atoms; such as an acetylamino group and abenzoylamino group), alkoxycarbonylamino groups (each preferably having2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, andparticularly preferably 2 to 12 carbon atoms; such as amethoxycarbonylamino group), aryloxycarbonylamino groups (eachpreferably having 7 to 20 carbon atoms, more preferably 7 to 16 carbonatoms, and particularly preferably 7 to 12 carbon atoms; such as aphenyloxycarbonylamino group), sulfonylamino groups (each preferablyhaving 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, andparticularly preferably 1 to 12 carbon atoms; such as amethanesulfonylamino group and a benzenesulfonylamino group), sulfamoylgroups (each preferably having 0 to 20 carbon atoms, more preferablyfrom 0 to 16 carbon atoms, and particularly preferably from 0 to 12carbon atoms; such as a sulfamoyl group, methylsulfamoyl group,dimethylsulfamoyl group, and a phenylsulfamoyl group), carbamoyl groups(each preferably having 1 to 20 carbon atoms, more preferably 1 to 16carbon atoms, and particularly preferably 1 to 12 carbon atoms; such asa carbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group,and a phenylcarbamoyl group), alkylthio groups (each preferably having 1to 20 carbon atoms, more preferably 1 to 16 carbon atoms, andparticularly preferably 1 to 12 carbon atoms; such as a methylthio groupand an ethylthio group), arylthio groups (each preferably having 6 to 20carbon atoms, more preferably 6 to 16 carbon atoms, and particularlypreferably 6 to 12 carbon atoms; such as a phenylthio group), sulfonylgroups (each preferably having 1 to 20 carbon atoms, more preferably 1to 16 carbon atoms, and particularly preferably 1 to 12 carbon atoms;such as a mesyl group and a tosyl group), sulfinyl groups (eachpreferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbonatoms, and particularly preferably 1 to 12 carbon atoms; such as amethanesulfinyl group and benzenesulfinyl group), ureido groups (eachpreferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbonatoms, and particularly preferably 1 to 12 carbon atoms; such as anureido group, a methylureido group, and a phenylureido group),phosphoric acid amide groups (each preferably having 1 to 20 carbonatoms, more preferably 1 to 16 carbon atoms and particularly preferably1 to 12 carbon atoms; such as a diethylphosphoric acid amide group andphenylphosphoric acid amide group), a hydroxyl group, a mercapto group,halogen atoms (for instance, a fluorine atom, a chlorine atom, a bromineatom and an iodine atom), a cyano group, a sulfo group, a carboxylgroup, a nitro group, a hydroxamic acid group, a sulfino group, ahydrazino group, an imino group, heterocyclic groups (each preferablyhaving 1 to 30 carbon atoms and more preferably 1 to 12 carbon atoms andincluding a nitrogen atom, an oxygen atom or a sulfur atom as aheteroatom; specifically such as an imidazolyl group, a pyridyl group, aquinolyl group, a furyl group, a thienyl group, a piperidyl group, amorpholino group, a benzoxazolyl group, a benzoimidazolyl group, abenzothiazolyl group, a carbazolyl group, an azepinyl group, and anoxiranyl group) and silyl groups (each preferably having 3 to 40 carbonatoms, more preferably 3 to 30 carbon atoms and particularly preferably3 to 24 carbon atoms; such as a trimethylsilyl group and atriphenylsilyl group).

These substituents may be further substituted. When there are two ormore substituents, each substituent may be same or different. Ifpossible, the substituents may combine with each other to form a ring.

Each of R² and R³ is preferably an alkyl group, an aryl group, analkenyl group, an alkynyl group, or a group obtained by allowing one ofthese groups to be substituted by substituent(s). From the viewpoint ofthe dissolution inhibiting effect, the sum of the numbers of carbonatoms of R² and R³ is preferably no less than 6, more preferably no lessthan 8 and most preferably no less than 10.

The X⁻ is an anion that is a conjugate base of an arbitrary organic acidor inorganic acid, and may be a high molecular compound or a lowmolecular compound, and may be a polyvalent anion. Examples of theseanions may include anions, which are organic acid conjugate bases, suchas R^(a1)—SO₃ ⁻, R^(a1)—SO₂ ⁻, R^(a1)—CO₂ ⁻, R^(a1)—CS₂ ⁻, R^(a1)—O—CS₂⁻, R^(a1)—S—CS₂ ⁻, R^(a1)—O—PO₂ ⁻, (R^(a1)—O)₂PO₂ ⁻, R^(a1)(R^(a1)—O)PO₂⁻, R^(a1)-EW¹-Z⁻-EW²—R^(a1), (R^(a1))₄B⁻ and Ar^(x)O⁻ or anions, whichare inorganic acid conjugate bases, such as F⁻, Cl⁻, Br⁻, I⁻, PF₆ ⁻, BF₄⁻, SbF₆ ⁻, ClO₄ ⁻, SO₄ ²⁻, NO₃ ⁻, CO₃ ²⁻, SCN⁻, CN⁻, SiF₆ ⁻, FSO₃ ⁻, I₃⁻, Br₃ ⁻ and IBr₂ ⁻.

Here, the R^(a1) represents an organic substituent selected from alkylgroups, alkenyl groups, alkynyl groups, aryl groups, aralkyl groups, andgroups each obtained by further substituting one of these groups with(a) substituent(s). When a plurality of R^(a1)s are present in amolecule, each R^(a1) may be same or different and may be bonded toanother R^(a1) to form a ring. EW¹ and EW² each independently representan electron attractive group and specific examples thereof may include—SO—, —CO—, —SO₂— and —CN. Z represents —CR^(z1)— (R^(z1) represents ahydrogen atom or a substituent), or —N—. Ar^(x) represents an arylgroup.

Among compounds represented by the general formula (1-1), as apreferable example, compounds represented by the following generalformula (1-1-a) can be cited.

The definition of each of R², R³ and X⁻ in the general formula (1-1-a)are the same as in the general formula (1-1), and the preferable rangesthereof are also the same. R² and R³ in the general formula (1-1-a) eachfurther preferably are an alkyl group, an aryl group, an alkenyl group,an alkynyl group, or a group obtained by allowing one of these groups tobe substituted by an arbitrary substituent(s). From the viewpoint of thedissolution inhibiting effect, the sum of the numbers of carbon atoms ofR² and R³ is preferably no less than 6, more preferably no less than 8,and most preferably no less than 10.

In the general formula (1-1-a), R⁴ though R⁷ each independentlyrepresent a hydrogen atom or a substituent. As the substituent, thesubstituents cited as examples of R² and R³ in the general formula (1-1)can be cited. Any two of R⁴ though R⁷ may be same as or different fromeach other and may combine with each other to form a ring structure. R⁴though R⁷ each may combine with L¹, R² or R³ to form a ring structure.In the case where the bond between L¹ and C¹ carbon or between L¹ and C²carbon is a double bond or a triple bond, some of R⁴ though R⁷ may notexist in accordance with the existence of the double or triple bond.

In the general formula (1-1-a), L¹ represents a divalent linkage groupor a single bond, which, together with —C¹—N¹—C²—, forms a ringstructure. In the case where L¹ is a divalent linkage group, L¹ may havea substituent. Preferred examples of the ring structure containing L¹are three- to ten-membered ring structure. From the viewpoint ofefficiency of removing dissolution inhibiting effect, 3- to 8-memberedrings are preferable. In view of the suitability for synthesis,5-membered rings and 6-membered rings are preferable.

In the general formula (1-1-a), R⁴ and R⁵ may represent an identicalatom or an identical substituent so that the bond between C¹ and R⁴(i.e. R⁵) becomes a double bond. Also, R⁶ and R⁷ may represent anidentical atom or an identical substituent so that the bond between C²and R⁶ (i.e. R⁷) becomes a double bond. (For instance, in the case ofR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

Among compounds that are represented by the general formula (1-1), aspreferable examples, compounds that are represented by the followinggeneral formula (1-1-b) can be cited.

In the general formula (1-1-b), R², R³ and X⁻ each have the samedefinition respectively as R², R³ or X⁻ in the general formula (1-1),and the preferable ranges are also the same.

In the general formula (1-1-b), R⁴ through R¹¹ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (1-1) can be cited. Any two of R⁴ through R¹¹ may be the same asor different from each other and may combine with each other to form aring structure. R⁴ through R¹¹ each may combine with L², R² or R³ toform a ring structure. The bond between C³ carbon atom and C¹ carbonatom, between C⁴ carbon atom and C² carbon atom, between C³ carbon atomand L², or between C⁴ carbon atom and L² may be a double bond or atriple bond. In such a case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of such double or triple bond. Further, L²itself may be a double bond connecting C³ carbon atom and C⁴ carbonatom. Also in this case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of the double bond.

In the general formula (1-1-b), L² represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴ or a double bond connecting C³ and C⁴. In thecase where L² represents a divalent linkage group, L² may havesubstituent(s). As preferable examples of the ring structure thatcontains L², 5- to 10-membered rings can be cited. From the viewpoint ofthe efficiency of removing the dissolution inhibition, 5- to 8-memberedrings are preferable, and when further considering the suitability forsynthesis, 5- and 6-membered rings are preferable.

In the general formula (1-1-b), two substituents which are selected fromR⁴ through R¹¹ and are bonded to the same atom may be an identical atomor substituent so that a double bond is formed. (For instance, providedR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (1-1-b), two substituents which are selected fromR⁴ through R¹¹ and are bonded to atoms adjoining each other may be anidentical atom or substituent so that a 3-membered ring is formed. (Forinstance, provided R⁴═R⁸=oxygen atom, an epoxy group may be formed.)

Among compounds that are represented by the general formula (1-1), aspreferable examples, compounds that are represented by the followinggeneral formula (1-1-c) can be cited.

In the general formula (1-1-c), R² and X⁻ each have the same definitionrespectively as R² or X⁻ in the general formula (1-1), and thepreferable range is also the same. As R² in the general formula (1-1-c),more preferably, an alkyl group, an aryl group, an alkenyl group, analkynyl group, or a group obtained by allowing one of these groups to besubstituted by arbitrary substituent(s) can be cited. From the viewpointof the dissolution inhibition, R² has preferably no less than 2 carbonatoms, more preferably no less than 3 carbon atoms and particularlypreferably, no less than 4 carbon atoms.

In the general formula (1-1-c), R⁴ through R¹³ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (1-1) can be cited. Any two of R⁴ through R¹³ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹³ each may combine with L² or R²to form a ring structure. The bond between C³ carbon atom and C¹ carbonatom, between C⁴ carbon atom and C² carbon atom, between C³ carbon atomand L², or between C⁴ carbon atom and L² may be a double bond or atriple bond. In such a case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of such double or triple bond. Further, L²itself may be a double bond connecting C³ carbon atom and C⁴ carbonatom. Also in this case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of the double bond.

In the general formula (1-1-c), Ar¹ represents an aromatic ring group,preferably represents a substituted and non-substituted phenyl group,naphthyl group, anthranyl group, phenanthrenyl group, pyridyl group,pyrazyl group, imidazolyl group, quinolyl group, indolyl group,isoquinolyl group, pyrrolyl group, furanyl group, pyrazolyl group,triazolyl group, tetrazolyl group, oxazolyl group, oxadiazolyl group,thiazolyl group, pyrimidinyl group or the like. Ar¹ may combine with anyone of L², R², R⁴ through R¹³ to form a ring structure.

In the general formula (1-1-c), n represents an integer which is no lessthan 0, preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, andparticularly preferably 0 or 1. When n is no less than 2, there are aplurality of R¹²s and a plurality of R¹³s. Any two of such a pluralityof R¹²s and a plurality of R¹³s may be the same as each other ordifferent from each other and may combine with each other to form a ringstructure.

In the general formula (1-1-c), L² represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴, or a double bond connecting C³ and C⁴. In thecase where L² represents a divalent linkage group, L² may have asubstituent. As preferable examples of the ring structure containing L²,5- to 10-membered rings can be preferably cited. In view of theefficiency of removing dissolution inhibiting effect, 5- to 8-memberedrings are preferable, and in view of the suitability for synthesis, 5-and 6-membered rings are preferable.

In the general formula (1-1-c), two substituents which are selected fromR⁴ through R¹³ and are bonded to the same atom may be an identical atomor substituent so that a double bond is formed. (For instance,provided-R⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (1-1-c), two substituents which are selected fromR⁴ through R¹³ and are bonded to atoms adjoining each other may be anidentical atom or substituent so that a 3-membered ring is formed. (Forinstance, provided R⁴═R⁸=oxygen atom, an epoxy group may be formed.)

Among compounds represented by the general formula (1-1), as apreferable example, compounds represented by the following generalformula (1-1-d) can be cited.

In the general formula (1-1-d), R² and X⁻ each have the same definitionrespectively as R² or X⁻ in the general formula (1-1), and thepreferable range is also the same. As R² in the general formula (1-1-d),more preferably, an alkyl group, an aryl group, an alkenyl group, analkynyl group, or a group obtained by allowing one of these groups to besubstituted by arbitrary substituent(s) can be cited. From the viewpointof the dissolution inhibition, R² has preferably no less than 2 carbonatoms, more preferably no less than 3 carbon atoms and particularlypreferably, no less than 4 carbon atoms.

In the general formula (1-1-d), R⁴ through R¹⁴ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (1-1) can be cited. Any two of R⁴ through R¹⁴ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹⁴ each may combine with L², R² orR³ to form a ring structure. The bond between C³ carbon atom and C¹carbon atom, between C⁴ carbon atom and C² carbon atom, between C³carbon atom and L², or between C⁴ carbon atom and L² may be a doublebond or a triple bond. In such a case, some of R⁴ through R¹¹ do/doesnot exist in accordance with the existence of such double or triplebond. Further, L² itself may be a double bond connecting C³ carbon atomand C⁴ carbon atom. Also in this case, some of R⁴ through R¹¹ do/doesnot exist in accordance with the existence of the double bond.

In the general formula (1-1-d), m represents an integer from 0 to 5.When m is no less than 2, there are a plurality of R¹⁴s. Any two of sucha plurality of R¹⁴s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (1-1-d), n represents an integer which is no lessthan 0, preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, andparticularly preferably 0 or 1. When n is no less than 2, there are aplurality of R¹²s and a plurality of R¹³s. Any two of such a pluralityof R¹²s and a plurality of R¹³s may be the same as each other ordifferent from each other and may combine with each other to form a ringstructure.

In the general formula (1-1-d), L² represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴, or a double bond connecting C³ and C⁴. In thecase where L² represents a divalent linkage group, L² may have asubstituent. As preferable examples of the ring structure containing L²,5- to 10-membered rings can be preferably cited. In view of theefficiency of removing dissolution inhibiting effect, 5- to 8-memberedrings are preferable, and in view of the suitability for synthesis, 5-and 6-membered rings are preferable.

In the general formula (1-1-d), two substituents which are selected fromR⁴ through R¹⁴ and are bonded to the same atom may be an identical atomor substituent so that a double bond is formed. (For instance, providedR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (1-1-d), two substituents which are selected fromR⁴ through R¹⁴ and are bonded to atoms adjoining each other may be anidentical atom or substituent so that a 3-membered ring is formed. (Forinstance, provided R⁴═R⁸=oxygen atom, an epoxy group may be formed.)

Among compounds represented by the general formula (1-1), as apreferable example, compounds represented by the following generalformula (1-1-e) can be cited.

In the general formula (1-1-e), R² and X⁻ each have the same definitionrespectively as R² or X⁻ in the general formula (1-1), and thepreferable range is also the same. As R² in the general formula (1-1-d),more preferably, an alkyl group, an aryl group, an alkenyl group, analkynyl group, or a group obtained by allowing one of these groups to besubstituted by arbitrary substituent(s) can be cited. From the viewpointof the dissolution inhibition, R² has preferably no less than 2 carbonatoms, more preferably no less than 3 carbon atoms and particularlypreferably, no less than 4 carbon atoms.

In the general formula (1-1-e), R⁴ through R¹⁴ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (1-1) can be cited. Any two of R⁴ through R¹⁴ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹⁴ each may combine with L³ or R²to form a ring structure. The bond between C³ carbon atom and C¹ carbonatom, between C⁴ carbon atom and C² carbon atom, between C³ carbon atomand L³, or between C⁴ carbon atom and L³ may be a double bond or atriple bond. In such a case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of such double or triple bond. Further, L³itself may be a double bond connecting C³ carbon atom and C⁴ carbonatom. Also in this case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of the double bond.

In the general formula (1-1-e), m represents an integer from 0 to 5.When m is no less than 2, there are a plurality of R¹⁴s. Any two of sucha plurality of R¹⁴s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (1-1-e), n represents an integer which is no lessthan 0, preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, andparticularly preferably 0 or 1. When n is no less than 2, there are aplurality of R¹²s and a plurality of R¹³s. Any two of such a pluralityof R¹²s and a plurality of R¹³s may be the same as each other ordifferent from each other and may combine with each other to form a ringstructure.

In the general formula (1-1-e), L³ represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴, or a double bond connecting C³ and C⁴. As thedivalent linkage group, —O—, —S—, —N(R^(L1))—, or —C(R^(L2))(R^(L3))— ispreferable. R^(L1) through R^(L3) are selected from the group consistingof a hydrogen atom and the substituents that can be represented by R² orR³ in the general formula (1-1). Each R^(L1) through R^(L3) may bebonded to any one of R² and R⁴ through R¹⁴ to form a ring structure.When the bond between C³ and L³ or between C⁴ and L³ is a double bond,some of R^(L1) through R^(L3) do/does not exist in accordance with theexistence of the double bond.

In the general formula (1-1-e), two substituents which are selected fromR⁴ through R¹⁴ and R^(L1) through R^(L3) and are bonded to the same atommay be an identical atom or substituent so that a double bond is formed.(For instance, provided R⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (1-1-e), two substituents which are selected fromR⁴ through R¹⁴ and R^(L1) through R^(L3) and are bonded to atomsadjoining each other may be an identical atom or substituent so that a3-membered ring is formed. (For instance, provided R⁴═R⁸=oxygen atom, anepoxy group may be formed.)

Among compounds represented by the general formula (1-1), as apreferable example, compounds represented by the following generalformula (1-1-f) can be cited.

In the general formula (1-1-f), R⁴ through R¹⁷ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (1-1) can be cited. Any two of R⁴ through R¹⁷ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹⁷ each may combine with L³, R² orR³ to form a ring structure. The bond between C³ carbon atom and C¹carbon atom, between C⁴ carbon atom and C² carbon atom, between C³carbon atom and L³, or between C⁴ carbon atom and L³ may be a doublebond or a triple bond. In such a case, some of R⁴ through R¹¹ do/doesnot exist in accordance with the existence of such double or triplebond. Further, L³ itself may be a double bond connecting C³ carbon atomand C⁴ carbon atom. Also in this case, some of R⁴ through R¹¹ do/doesnot exist in accordance with the existence of the double bond.

In the general formula (1-1-f), m1 and m2 each independently representan integer from 0 to 5. When m1 or m2 is no less than 2, there are aplurality of R¹⁴s or a plurality of R¹⁷s. Any two of such a plurality ofR¹⁴s or R¹⁷s may be the same as each other or different from each otherand may combine with each other to form a ring structure.

In the general formula (1-1-f), n1 and n2 each independently representan integer which is no less than 0, preferably 0, 1, 2 or 3, morepreferably 0, 1 or 2, and particularly preferably 0 or 1. When n1 is noless than 2, there are a plurality of R¹²s and a plurality of R¹³s. Anytwo of such a plurality of R¹²s and a plurality of R¹³s may be the sameas each other or different from each other and may combine with eachother to form a ring structure. Similarly, when n2 is no less than 2,there are a plurality of R¹⁵s and a plurality of R¹⁶s. Any two of such aplurality of R¹⁵s and a plurality of R¹⁶s may be the same as each otheror different from each other and may combine with each other to form aring structure.

In the general formula (1-1-f), L³ represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴, or a double bond connecting C³ and C⁴. As thedivalent linkage group, —O—, —S—, —N(R^(L1))—, or —C(R^(L2))(R^(L3))— ispreferable. R^(L1) through R^(L3) are selected from the group consistingof a hydrogen atom and the substituents that can be represented by R² orR³ in the general formula (1-1). Each R^(L1) through R^(L3) may bebonded to any one of R² and R⁴ through R¹⁷ to form a ring structure.When the bond between C³ and L³ or between C⁴ and L³ is a double bond,some of R^(L1) through R^(L3) do/does not exist in accordance with theexistence of the double bond.

In the general formula (1-1-f), two substituents which are selected fromR⁴ through R¹⁷ and R^(L1) through R^(L3) and are bonded to the same atommay be an identical atom or substituent so that a double bond is formed.(For instance, provided R⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (1-1-f), two substituents which are selected fromR⁴ through R¹⁷ and R^(L1) through R^(L3) and are bonded to atomsadjoining each other may be an identical atom or substituent so that a3-membered ring is formed. (For instance, provided R⁴═R⁸=oxygen atom, anepoxy group may be formed.)

In the following, specific examples of compounds represented by thegeneral formula (1-1) and preferably used in the invention are cited.However, any compounds that are represented by the general formula (1-1)can be selected and used. Accordingly, compounds usable in the inventionare not limited to the compounds cited below. The compounds shown by thecompound Nos. I-1 through I-62 are examples, whose N-containing ringsare 6-membered rings, and the compounds shown by the compound Nos. II-1through II-17 are examples, whose N-containing rings are 5-memberedrings. The compounds shown by the compound Nos. III-1 through III-17 areexamples, whose N-containing rings are 5-membered rings having methylgroups as substituents, and the compounds shown by the compound Nos.IV-1 through IV-17 are examples, whose N-containing rings are 6-memberedrings also including O therein. TABLE 1

Compound No. R¹ R² X⁻ I-1

I⁻ I-2

Br⁻ I-3

Br⁻ I-4

Br⁻ I-5

Br⁻ I-6

PF₆ ⁻ I-7

TsO⁻ I-8

BF₆ ⁻ I-9

TsO⁻ I-10

PF₆ ⁻ I-11

TsO⁻ I-12

Br⁻ I-13

TsO⁻

TABLE 2

Compound No. R¹ R² X I-14

PF₆ ⁻ I-15

TsO⁻ I-16

PF₆ ⁻ I-17

TsO⁻ I-18

PF₆ ⁻ I-19

TsO⁻ I-20

TsO⁻ I-21

TsO⁻ I-22

TsO⁻ I-23

TsO⁻ I-24

PF₆ ⁻ I-25

TsO⁻

TABLE 3

Compound No. R¹ R² X I-26

TsO⁻ I-27

TsO⁻ I-28

TsO⁻ I-29

TsO⁻ I-30

TsO⁻ I-31

TsO⁻ I-32

Br⁻ I-33

TsO⁻ I-34

TsO⁻

TABLE 4

Compound No. R¹ R² X I-35

BF₄ ⁻ I-36

TsO⁻ I-37

BF₄ ⁻ I-38

Br⁻ I-39

Br⁻ I-40

Br⁻ I-41

TsO⁻ I-42

TsO⁻ I-43

Br⁻

TABLE 5

Compound No. R¹ R² X⁻ I-44

Br⁻ I-45

PF₆ ⁻ I-46

BF₄ ⁻ I-47

TsO⁻ I-48

Br⁻ I-49

PF₆ ⁻ I-50

Br⁻ I-51

TsO⁻ I-52

TsO⁻

TABLE 6

Compound No. R¹ R² X I-53

PF₆ ⁻ I-54

Br⁻ I-55

Br⁻ I-56

TsO⁻ I-57

PF₆ ⁻ I-58

Br⁻ I-59

TsO⁻ I-60

PF₆ ⁻ I-61

Br⁻ I-62

TsO⁻

TABLE 7

Compound No. R¹ R² X⁻ II-1

I⁻ II-2

PF₆ ⁻ II-3

TsO⁻ II-4

TsO⁻ II-5

Br⁻ II-6

PF₆ ⁻ II-7

Br⁻ II-8

TsO⁻ II-9

Br⁻ II-10

PF₆ ⁻

TABLE 8

Compound No. R¹ R² X⁻ II-11

Br⁻ II-12

TsO⁻ II-13

TsO⁻ II-14

TsO⁻ II-15

TsO⁻ II-16

TsO⁻ II-17

TsO⁻

TABLE 9

Compound No. R¹ R² X⁻ III-1

I⁻ III-2

PF₆ ⁻ III-3

Br⁻ III-4

Br⁻ III-5

Br⁻ III-6

PF₆ ⁻ III-7

Br⁻ III-8

TsO⁻ III-9

Br⁻ III-10

PF₆ ⁻ III-11

Br⁻

TABLE 10

Compound No. R¹ R² X⁻ III-12

TsO⁻ III-13

TsO⁻ III-14

TsO⁻ III-15

TsO⁻ III-16

TsO⁻ III-17

TsO⁻

TABLE 11

Compound No. R¹ R² X⁻ IV-1

I⁻ IV-2

PF₆ ⁻ IV-3

Br⁻ IV-4

Br⁻ IV-5

Br⁻ IV-6

PF₆ ⁻ IV-7

Br⁻ IV-8

TsO⁻ IV-9

Br⁻ IV-10

PF₆ ⁻ IV-11

Br⁻

TABLE 12

Compound No. R¹ R² X⁻ IV-12

TsO⁻ IV-13

TsO⁻ IV-14

TsO⁻ IV-15

TsO⁻ IV-16

TsO⁻ IV-17

TsO⁻

Furthermore, the following various compounds shown by the compound Nos.V-1 through V-20 are also preferably used as the compounds that arerepresented by the general formula (1-1) and can exhibit an effectaccording to the invention.

The compound represented by the general formula (1-1) that is used in animage forming material according to the invention may be used singly ora multiple kinds of the compounds represented by the general formula(1-1) may be used in combination. The content of the compoundrepresented by the general formula (1-1) is, from the viewpoint of thefilm formability, preferably not higher than 50% based on the mass of awhole solids content in an image forming layer. From the viewpoint ofexcellent image formability, the content is preferably in the range offrom 0.1 to 30% based on the mass of a whole solids content in an imageforming layer. And from the viewpoint of providing both of excellentimage formability and excellent printing properties such as printingdurability, the content is most preferably in the range of from 0.5 to15% based on the mass of a whole solids content in an image forminglayer.

((C) Onium Salts Represented by General Formula (1-2))

A second image forming layer according to the invention includes anonium salt (particular onium salt) represented by the following generalformula (1-2).X⁻M⁺  General formula (1-2)

(In the general formula (1-2), X⁻ represents an anion that has at leastone substituent having an alkali dissociative proton. M⁺ represents acounter cation selected from sulfonium, iodonium, ammonium, phosphoniumand oxonium.)

It is considered that when an onium salt represented by the generalformula (1-2) is added to an image forming layer, the onium salt canachieve a solubility improvement only in an exposed portion withoutsubstantially damaging the dissociation inhibition power due to astructure of an onium mother nucleus in an unexposed portion and thatthis effect of the onium salt is caused by the alkali dissociativesubstituent on the counter anion. Further, it is considered that in theheat-example exposure system, the flexibility of the matrix is improvedowing to strong heat generation during the exposure, and, at thismoment, the degree of freedom of movement in the film is improved. Thecounter anion, not fixed to the cation mother nucleus through a covalentbond, has high degree of freedom of movement during the exposure andtends to cause a large positional change. It is inferred that theresultant change, that is, removing of the dissolution inhibiting effectin an exposed portion, can be maintained even after the instantaneousheat generated by the exposure disappears, and the storability afterexposure is improved thereby.

Accordingly, it is considered that such particular onium salt in animage forming layer, together with the action of the particular novolacresin, contributes to the excellent effect of the invention.

In the following, the onium salt represented by the general formula(1-2) will be detailed.

As the substituent having an alkali dissociative proton in an anionexpressed by the X⁻, a phenolic hydroxyl group (Ar—OH), a carboxyl group(—COOH), a mercapto group (—SH), a phosphonic acid group (—PO₃H₂), aphosphoric acid group (—OPO₃H₂), a sulfonamide group (—SO₂NH₂, —SO₂NHR),a substituted sulfonamide type acidic group (hereinafter, referred to as“active imide group”; such as —SO₂NHCOR, —SO₂NHSO₂R, —CONHSO₂R), asulfonic acid group (—SO₃H), a sulfinic acid group (—SO₂H), a—C(CF₃)₂OH, or a —COCH₂COCF₃ can be preferably used. Here, Ar representsan aryl group that may have a substituent, and R represents ahydrocarbon group that may have a substituent. As the substituents thatprovide excellent balance between the dissolution inhibiting effect andthe sensitivity, a phenolic hydroxyl group, a carboxyl group, a mercaptogroup, a sulfonamide group, an active imide group, a —C(CF₃)₂OH and—COCH₂COCF₃ can be cited. A phenolic hydroxyl group and a carboxyl groupare most preferable.

X⁻ preferably represents an anion which is a conjugate base of Broenstedacid and more preferably represents an anion which is a conjugate baseof an organic acid. The organic acid can be selected from sulfonicacids, carboxylic acids, phosphonic acids, phenols, active imides andsulfinic acids. The organic acid has pKa which is preferably smallerthan 3 and more preferably smaller than 1. The organic acid isparticularly preferably a sulfonic acid.

The counter cation expressed by M⁺ is selected from sulfonium ions,iodonium ions, ammonium ions, phosphonium ions, and oxonium ions. Fromthe viewpoint of the dissolution inhibiting effect, sulfonium ions,iodonium ions and quaternary ammonium ions are preferable, andquaternary ammonium ions are most preferable.

As a preferable example of the quaternary ammonium, a structurerepresented by the following general formula (M) can be cited.

In the general formula (M), R^(m1) through R^(m4) each independentlyrepresent a substituent that contains one or more carbon atoms and anytwo of R^(m1) through R^(m4) may combine with each other to form a ringstructure.

As the substituents including one or more carbon atoms represented bythe R^(m1) through R^(m4), the following ones can be exemplified.

For instance, alkyl groups (each preferably having 1 to 20 carbon atoms,more preferably 1 to 16 carbon atoms, and particularly preferably 1 to12 carbon atoms; specifically, such as a methyl group, an ethyl group,an n-butyl group, an iso-propyl group, a tert-butyl group, an n-octylgroup, an n-decyl group, an n-hexadecyl group, a cyclopropyl group, acyclopentyl group, a cyclohexyl group, and a 2-cyclohexylethyl group),alkenyl groups (each preferably having 2 to 20 carbon atoms, morepreferably 2 to 12 carbon atoms, and particularly preferably 2 to 8carbon atoms; such as a vinyl group, an allyl group, a 2-butenyl group,a 3-pentenyl group, a 2-cyclohexenylmethyl group), alkynyl groups (eachpreferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbonatoms, and particularly preferably 2 to 8 carbon atoms; such as apropargyl group and a 3-pentynyl group), aryl groups (each preferablyhaving 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, andparticularly preferably 6 to 12 carbon atoms; such as a phenyl group, ap-methyl phenyl group, and a naphthyl group) can be cited.

These substituents may be further substituted. When a substituentrepresented by R^(m1) through R^(m4) has a plurality of such furthersubstituents, any two of such further substituents may be same as eachother or different from each other, and may be bonded to form a ring.

Each R^(m1) through R^(m4) is preferably an alkyl group, an aryl group,or a group obtained by allowing an alkyl group or an aryl group to besubstituted by arbitrary substituent(s). From the viewpoint of thealkali-resistance of an image portion, a sum of the numbers of carbonatoms of the R^(m1) through R^(m4) is preferably from 8 to 80, morepreferably from 10 to 64 and particularly preferably from 12 to 48. Whenthe sum of the numbers of the carbon atoms is too few, since thehydrophilicity of the molecule becomes too high, the water resistancesometimes becomes poor. On the other hand, when the sum of the numbersof the carbon atoms is too much, the influence of the cation portion isdiminished, and the dissolution inhibiting effect is sometimesdeteriorated.

As a preferable example of the quaternary ammonium, a structurerepresented by the following general formula (M-1) can be cited.

In the general formula (M-1), R¹ represents a residue that, togetherwith N¹ atom, forms a ring structure. R² and R³ each independentlyrepresent an organic group and may be bonded to each other to form aring structure. At least one of R² and R³ may be bonded to R¹ to form aring structure.

The residue represented by R¹ may be any divalent organic group that,together with forms N¹ atom, forms a ring structure. The ring structureis not limited to a hydrocarbon-based ring structure and may contain aplurality of nitrogen atoms or may include another hetero atom such asan oxygen atom or a sulfur atom. The ring structure may include a doublebond therein and may be polycyclic.

As a preferable example of the ring structure formed by R¹ and N¹, 3- to10-membered rings can be cited. From the viewpoint of efficientlyremoving the dissolution inhibiting effect, 3- to 8-membered rings arepreferable. And in view of the suitability for synthesis, 5- and6-membered rings are preferable.

The ring structure formed by R¹ and N¹ may have a substituent and as thesubstituent that can be introduced, an alkyl group, an aryl group, ahalogen atom or the like can be cited.

Each R² and R³ may be same or different and may be arbitrarily selectedfrom organic groups. However, in view of the inhibition, that is, inview of exhibiting a strong dissolution inhibiting effect, it ispreferable that R² and R³ each independently represent an aryl group, agroup represented by the following general formula (2-2), or such analkyl group that the sum of the numbers of the carbon atoms of R² and R³is no less than 6. Preferably, at least one of R² and R³ has a branchedstructure or a ring structure. Furthermore, in view of the efficiency ofremoving the dissolution inhibiting effect, preferably, at least one ofR² and R³ contains an aromatic ring, and more preferably, both R² and R³contain aromatic rings.

In the general formula (2-2), each R⁴, R⁵ and R⁶ represents any possiblesubstituent and may be same or different. Any two of R⁴, R⁵, and R⁶ maybe bonded to each other to form a ring. The bond between R⁴ or R⁵ and C¹may be a double bond and in such a case, R⁴ and R⁵ represent anidentical group. And n represents an integer of 0 or 1. Further, mrepresents an integer from 0 to 5. When there are a plurality of R⁶s,any two of such R⁶s may be the same as each other or different from eachother, and may combine with each other to form a ring structure. In thecase where n is 1, from the viewpoint of the suitability for synthesis,it is preferable that at least one of R⁴ and R⁵ is a hydrogen atom andit is most preferable that both of R⁴ and R⁵ are hydrogen atoms.

As the substituents represented by the R² and R³, the followings can becited. For instance, alkyl groups (preferably having 1 to 20 carbonatoms, more preferably 1 to 16 carbon atoms, and particularly preferably1 to 12 carbon atoms, specifically, such as a methyl group, an ethylgroup, an n-butyl group, an iso-propyl group, a tert-butyl group, ann-octyl group, an n-decyl group, an n-hexadecyl group, a cyclopropylgroup, a cyclopentyl group, a cyclohexyl group, and a 2-cyclohexylethylgroup), alkenyl groups (preferably having 2 to 20 carbon atoms, morepreferably 2 to 12 carbon atoms, and particularly preferably 2 to 8carbon atoms, such as a vinyl group, an allyl group, a 2-betenyl group,a 3-pentenyl group, and a 2-cyclohexenylmethyl group), alkynyl groups(preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbonatoms, and particularly preferably 2 to 8 carbon atoms, such as apropargyl group and a 3-pentynyl group), aryl groups (preferably having6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, andparticularly preferably 6 to 12 carbon atoms, such as a phenyl group, ap-methyl phenyl group, and a naphthyl group), amino groups (preferablyhaving 0 to 20 carbon atoms, more preferably 0 to 12 carbon atoms, andparticularly preferably 0 to 6 carbon atoms, such as an amino group, amethylamino group, a dimethylamino group, a diethylamino group, adiphenylamino group, and a dibenzylamino group), alkoxy groups(preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbonatoms, and most preferably 1 to 8 carbon atoms, such as a methoxy group,an ethoxy group, and a butoxy group), aryloxy groups (preferably having6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms, andparticularly preferably 6 to 12 carbon atoms, such as a phenyloxy groupand a 2-naphthyloxy group), acyl groups (preferably having 1 to 20carbon atoms, more preferably 1 to 16 carbon atoms, and particularlypreferably 1 to 12 carbon atoms, such as an acetyl group, a benzoylgroup, a formyl group, and a pivaloyl group), alkoxycarbonyl groups(preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbonatoms, and particularly preferably 2 to 12 carbon atoms, such as amethoxycarbonyl group and an ethoxycarbonyl group), aryloxycarbonylgroups (preferably having 7 to 20 carbon atoms, more preferably 7 to 16carbon atoms, and particularly preferably 7 to 10 carbon atoms, such asa phenyloxycarbonyl group), acyloxy groups (preferably having 2 to 20carbon atoms, more preferably 2 to 16 carbon atoms, and particularlypreferably 2 to 10 carbon atoms, such as an acetoxy group and abenzoyloxy group), acylamino groups (preferably having 2 to 20 carbonatoms, more preferably 2 to 16 carbon atoms, and particularly preferably2 to 10 carbon atoms, such as an acetylamino group and a benzoylaminogroup), alkoxycarbonylamino groups (preferably having 2 to 20 carbonatoms, more preferably 2 to 16 carbon atoms, and particularly preferably2 to 12 carbon atoms, such as a methoxycarbonylamino group),aryloxycarbonylamino groups (preferably having 7 to 20 carbon atoms,more preferably 7 to 16 carbon atoms, and particularly preferably 7 to12 carbon atoms, such as a phenyloxycarbonylamino group), sulfonylaminogroups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16carbon atoms, and particularly preferably 1 to 12 carbon atoms, such asa methanesulfonylamino group and a benzenesulfonylamino group),sulfamoyl groups (preferably having 0 to 20 carbon atoms, morepreferably 0 to 16 carbon atoms, and particularly preferably 0 to 12carbon atoms, such as a sulfamoyl group, a methylsulfamoyl group, adimethylsulfamoyl group, and a phenylsulfamoyl group), carbamoyl groups(preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbonatoms, and particularly preferably 1 to 12 carbon atoms, such as acarbamoyl group, a methylcarbamoyl group, a diethylcarbamoyl group, anda phenylcarbamoyl group), alkylthio groups (preferably having 1 to 20carbon atoms, more preferably 1 to 16 carbon atoms, and particularlypreferably 1 to 12 carbon atoms, such as a methylthio group and anethylthio group), arylthio groups (preferably having 6 to 20 carbonatoms, more preferably 6 to 16 carbon atoms, and particularly preferably6 to 12 carbon atoms, such as a phenylthio group), sulfonyl groups(preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbonatoms, and particularly preferably 1 to 12 carbon atoms, such as a mesylgroup and a tosyl group), sulfinyl groups (preferably having 1 to 20carbon atoms, more preferably 1 to 16 carbon atoms, and particularlypreferably 1 to 12 carbon atoms, such as a methanesulfinyl group and abenzenesulfinyl group), ureido groups (preferably having 1 to 20 carbonatoms, more preferably 1 to 16 carbon atoms, and particularly preferably1 to 12 carbon atoms, such as a ureido group, a methylureido group, anda phenylureido group), phosphoric acid amide groups (preferably having 1to 20 carbon atoms, more preferably 1 to 16 carbon atoms andparticularly preferably 1 to 12 carbon atoms, such as adiethylphosphoric acid amide group and a phenylphosphoric acid amidegroup), a hydroxyl group, a mercapto group, halogen atoms (for instance,a fluorine atom, a chlorine atom, a bromine atom and an iodine atom), acyano group, a sulfo group, a carboxyl group, a nitro group, ahydroxamic acid group, a sulfino group, a hydrazino group, an iminogroup, a heterocyclic groups (preferably including 1 to 30 carbon atomsand more preferably 1 to 12 carbon atoms and further including anitrogen atom, an oxygen atom or a sulfur atom as a heteroatom, such asan imidazolyl group, a pyridyl group, a quinolyl group, a furyl group, athienyl group, a piperidyl group, a morpholino group, a benzoxazolylgroup, a benzoimidazolyl group, a benzothiazolyl group, a carbazolylgroup, an azepinyl group, and an oxiranyl group), and silyl groups(preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbonatoms and particularly preferably 3 to 24 carbon atoms, such as atrimethylsilyl group and a triphenylsilyl group) can be cited.

These substituents may be further substituted. Furthermore, when two ormore such further substituents are present, these may be the same as ordifferent from one another. Still furthermore, if possible, such pluralsubstituents may combine with each other to form a ring.

R² and R³ are each preferably an alkyl group, an aryl group, an alkenylgroup, an alkynyl group, or a group obtained by allowing one of thesegroups to be substituted by arbitrary substituent(s). Furthermore, inview of the dissolution inhibiting effect, a sum of the numbers ofcarbon atoms of R² and R³ is preferably 6 or more, more preferably 8 ormore, and most preferably 10 or more.

As a preferable example of the quaternary ammonium, a structurerepresented by the following general formula (M-2) can be cited.

In the general formula (M-2), R² and R³ each have the same definition asthat of R² or R³ in the general formula (M-1) and preferable rangesthereof are also the same. R² and R³ in the general formula (M-2) areeach preferably an alkyl group, an aryl group, an alkenyl group, analkynyl group, or a group obtained by allowing one of these groups to besubstituted by arbitrary substitutent(s). In view of the dissolutioninhibiting effect, a sum of the numbers of carbon atoms of R² and R³ ispreferably 6 or more, more preferably 8 or more, and most preferably 10or more.

Furthermore, in the general formula (M-2), R⁴ through R⁷ eachindependently represent a hydrogen atom or a substituent. Thesubstituent may be any of the substituents cited as examples of R² andR³ in the general formula (M-1). Any two of R⁴ through R⁷ may be thesame as or different from each other, and may combine with each other toform a ring structure. R⁴ through R⁷ each may combine with L¹, R² or R³to form a ring structure. In the case where the bond between L¹ and C¹carbon atom or between L¹ and C² carbon atom is a double bond or triplebond, some of R⁴ through R⁷ may not exist in accordance with theexistence of the double or triple bond.

In the general formula (M-2), L¹ represents a divalent linkage group ora single bond, which, together with —C¹—N¹—C²—, forms a ring structure.In the case where L¹ is a divalent linkage group, L¹ may have asubstituent. Preferred examples of a ring structure containing L¹ are 3-to 10-membered ring structure. From the viewpoint of efficiency ofremoving dissolution inhibiting effect, 3- to 8-membered rings arepreferable. In view of the suitability for synthesis, 5-membered ringsand 6-membered rings are preferable.

In the general formula (M-2), two substituents which are selected fromR⁴ through R⁷ and are bonded to the same atom may be an identical atomor substituent so that a double bond is formed. (For instance, providedR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

Among quaternary ammonium structures that are represented by the generalformula (1-1), as preferable examples, a structure represented by thefollowing general formula (M-3) can be cited.

In the general formula (M-3), R², R³ and X⁻ each have the samedefinition respectively as R², R³ or X⁻ in the general formula (M-1),and the preferable ranges thereof are also the same.

In the general formula (M-3), R⁴ through R¹¹ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (M-1) can be cited. Any two of R⁴ through R¹¹ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹¹ each may combine with L², R² orR³ to form a ring structure. The bond between C³ carbon atom and C¹carbon atom, between C⁴ carbon atom and C² carbon atom, between C³carbon atom and L², or between C⁴ carbon atom and L² may be a doublebond or a triple bond. In such a case some of R⁴ through R¹¹ do/does notexist in accordance with the existence of such double or triple bond.Further, L² itself may be a double bond connecting C³ carbon atom and C⁴carbon atom. Also in this case, some of R⁴ through R¹¹ do/does not existin accordance with the existence of the double bond.

In the general formula (M-3), L² represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴ or a double bond connecting C³ and C⁴. In thecase where L² represents a divalent linkage group, L² may havesubstituent(s). As preferable examples of the ring structure thatcontains L², 5- to 10-membered rings can be cited. From the viewpoint ofthe efficiency of removing the dissolution inhibition, 5- to 8-memberedrings are preferable, and when further considering the suitability forsynthesis, 5- and 6-membered rings are preferable.

In the general formula (M-3), two substituents which are selected fromR⁴ through R¹¹ and are bonded to the same atom may be an identical atomor substituent so that a double bond in formed. (For instance, providedR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (M-3), two substituents which are selected fromR⁴ through R¹¹ and are bonded to atoms adjoining each other may be anidentical atom or substituent so that a 3-membered ring is formed. (Forinstance, provided R⁴═R⁸=oxygen atom, an epoxy group may be formed.)

Among the quaternary ammonium structures represented by the generalformula (1-1), as a more preferable example, a structure represented bythe following general formula (M-4) can be cited.

In the general formula (M-4), R² has the same definition as that of R²in the general formula (M-1), and the preferable range is also the same.As R² in the general formula (M-4), more preferably, an alkyl group, anaryl group, an alkenyl group, an alkynyl group, or a group obtained byallowing one of these groups to be substituted by arbitrarysubstituent(s) can be cited. From the viewpoint of the dissolutioninhibition, R² has preferably no less than 2 carbon atoms, morepreferably no less than 3 carbon atoms and particularly preferably, noless than 4 carbon atoms.

In the general formula (M-4), R⁴ through R¹³ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (M-1) can be cited. Any two of R⁴ through R¹³ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹³ each may combine with L², R² orR³ to form a ring structure. The bond between C³ carbon atom and C¹carbon atom, between C⁴ carbon atom and C² carbon atom, between C³carbon atom and L², or between C⁴ carbon atom and L² may be a doublebond or a triple bond. In such a case some of R⁴ through R¹¹ do/does notexist in accordance with the existence of such double or triple bond.Further, L² itself may be a double bond connecting C³ carbon atom and C⁴carbon atom. Also in this case, some of R⁴ through R¹¹ do/does not existin accordance with the existence of the double bond.

In the general formula (M-4), Ar¹ represents an aromatic ring group.Preferable examples of the aromatic ring group include a phenyl group, anaphthyl group, an anthranyl group, a phenanthrenyl group, a pyridylgroup, a pyrazyl group, an imidazolyl group, a quinolinyl group, anindolyl group, an isoquinolinyl group, a pyrrolyl group, a furanylgroup, a pyrazolyl group, a triazolyl group, a tetrazolyl group, anoxazolyl group, an oxadiazolyl group, a thiazolyl group, and apyrimidinyl group, each of which may be substituted. Ar¹ may combinewith any one of L², R², R⁴ through R¹³ to form a ring structure.

In the general formula (M-4), n represents 0 or a positive integer, andis preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and particularlypreferably 0 or 1. When n is no less than 2, there are a plurality ofR¹²s and a plurality of R¹³s. Any two of such a plurality of R¹²s and aplurality of R¹³s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (M-4), L² represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure containing,a single bond connecting C³ and C⁴, or a double bond connecting C³ andC⁴. In the case where L² represents a divalent linkage group, L² mayhave a substituent. As a preferable example of a ring structurecontaining L², 5- to 10-membered rings can be preferably cited. In viewof the efficiency of removing dissolution inhibiting effect, 5- to8-membered rings are preferable, and in view of the suitability forsynthesis, 5- and 6-membered rings are preferable.

In the general formula (M-4), two substituents which are selected fromR⁴ through R¹³ and are bonded to the same atom may be an identical atomor substituent so that a double bond is formed. (For instance, providedR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (M-4), two substituents which are selected fromR⁴ through R¹³ and are bonded to atoms adjoining each other may be anidentical same atom or substituent so that a 3-membered ring is formed.(For instance, provided R⁴═R⁸═O, an epoxy group may be formed.)

Among the quaternary ammonium structures, as a preferable example, astructure represented by the following general formula (M-5) can becited.

In the general formula (M-5), R² has the same definition as that of R²in the general formula (M-1), and the preferable range is also the same.As R² in the general formula (M-5), more preferably, an alkyl group, anaryl group, an alkenyl group, an alkynyl group, or a group obtained byallowing one of these groups to be substituted by arbitrarilysubstituent(s) can be cited. From the viewpoint of the dissolutioninhibition, R² has preferably no less than 2 carbon atoms, morepreferably no less than 3 carbon atoms and particularly preferably noless than 4 carbon atoms.

In the general formula (M-5), R⁴ through R¹⁴ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (M-1) can be preferably cited. Any two of R⁴ through R¹⁴ be thesame as each other or different from each other and may combine witheach other to form a ring structure. R⁴ through R¹⁴ each may combinewith L², R², or R³ to form a ring structure. The bond between C³ carbonatom and C¹ carbon atom, between C⁴ carbon atom and C² carbon atom,between C³ carbon atom and L², or between C⁴ carbon atom and L² may be adouble bond or a triple bond. In such a case some of R⁴ through R¹¹do/does not exist in accordance with the existence of such double ortriple bond. Further, L² itself may be a double bond connecting C³carbon atom and C⁴ carbon atom. Also in this case, some of R⁴ throughR¹¹ do/does not exist in accordance with the existence of the doublebond.

In the general formula (M-5), m represents an integer from 0 to 5. Whenm is no less than 2, there are a plurality of R¹⁴s. Any two of such aplurality of R¹⁴s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (M-5), n represents 0 or a positive integer, andis preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and particularlypreferably 0 or 1. When n is no less than 2, there are a pluralities ofR¹²s and a plurality of R¹³s. Any two of such a plurality of R¹²s and aplurality of R¹³s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (M-5), L² represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴ or a double bond connecting C³ and C⁴. When L²represents a divalent linkage group, L² may have substituent(s). Aspreferable examples of the ring structure containing L², 5- to10-membered rings can be cited. In view of the efficiency of removingdissolution inhibiting effect, 5- to 8-membered rings are preferable,and in view of the suitability for synthesis, 5- and 6-membered ringsare preferable.

In the general formula (M-5), two substituents which are selected fromR⁴ through R¹⁴ and is bonded to the same atom may be an identical atomor substituent so that a double bond is formed. (For instance, providedR⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (M-5), two substituents which are selected fromR⁴ through R¹⁴ and are bonded to atoms adjoining each other may be anidentical atom or substituent so that a 3-membered ring is formed. (Forinstance, provided R⁴═R⁸═O, an epoxy group may be formed.)

Among the quaternary ammonium structures, as a further preferableexample, a structure represented by the following general formula (M-6)can be cited.

In the general formula (M-6), R² has the same definition as that of R²in the general formula (M-1), and the preferable range is also the same.As R² in the general formula (M-6), more preferably, an alkyl group, anaryl group, an alkenyl group, an alkynyl group, or a group obtained byallowing one of these groups by arbitrarily substituent(s) can be cited.From the viewpoint of the dissolution inhibition, R² has preferably noless than 2 carbon atoms, more preferably no less than 3 carbon atoms,and particularly preferably, no less than 4 carbon atoms.

In the general formula (M-6), R⁴ through R¹⁴ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that are cited as examples of R² and R³ in the generalformula (M-1) can be cited. Any two of R⁴ through R¹⁴ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹⁴ each may combine with L³ or R²to form a ring structure. The bond between C³ carbon atom and C¹ carbonatom, between C⁴ carbon atom and C² carbon atom, between C³ carbon atomand L³, or between C⁴ carbon atom and L³ may be a double bond or atriple bond. In such a case some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of such double or triple bond. Further, L³itself may be a double bond connecting C³ carbon atom and C⁴ carbonatom. Also in this case, some of R⁴ through R¹¹ do/does not exist inaccordance with the existence of the double bond.

In the general formula (M-6), m represents an integer from 0 to 5. Whenm is no less than 2, there are a plurality R¹⁴s. Any two of such aplurality of R¹⁴s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (M-6), n represents 0 or a positive integer, andis preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and particularlypreferably 0 or 1. When n is no less than 2, there are a plurality ofR¹²s and a plurality of R¹³s. Any two of such a plurality of R¹²s and aplurality of R¹³s may be the same as each other or different from eachother and may combine with each other to form a ring structure.

In the general formula (M-6), L³ represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴ or a double bond connecting C³ and C⁴. As thedivalent linkage group, —O—, —S—, —N(R^(L1))—, and —C(R^(L2))(R^(L3))—can be preferably cited. R^(L1) through R^(L3) are selected from thegroup consisting of a hydrogen atom and the substituents that can berepresented by R² and R³ in the general formula (M-1). Each R^(L1)through R^(L3) may be bonded to any one of R² and R⁴ through R¹⁴ to forma ring structure. When the bond between C³ and L³ or between C⁴ and L³is a double bond, some of R^(L1) through R^(L3) do/does not exist inaccordance with the existence of the double bond.

In the general formula (M-6), two substituents which are selected fromR⁴ through R¹⁴ and R^(L1) through R^(L3) and are bonded to the same atommay be an identical atom or substituent so that a double bond is formed.(For instance, provided R⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (M-6), two substituents which are selected fromR⁴ through R¹⁴ and R^(L1) through R^(L3) and are bonded to atomsadjoining each other may be an identical atom or substituent so that a3-membered ring is formed. (For instance, provided R⁴═R⁸═O, an epoxygroup may be formed.)

Among the quaternary ammonium structures, as a further preferableexample, a structure represented by the following general formula (M-7)can be cited.

In the general formula (M-7), R⁴ through R¹⁷ each independentlyrepresent a hydrogen atom or a substituent. As the substituent,substituents that were cited as examples of R² and R³ in the generalformula (M-1) can be cited. Any two of R⁴ through R¹⁷ may be the same aseach other or different from each other and may combine with each otherto form a ring structure. R⁴ through R¹⁷ each may combine with L³, R² orR³ to form a ring structure. The bond between C³ carbon atom and C¹carbon atom, between C⁴ carbon atom and C² carbon atom, between C³carbon atom and L³, or between C⁴ carbon atom and L³ may be a doublebond or a triple bond. In such a case some of R⁴ through R¹¹ do/does notexist in accordance with the existence of such double or triple bond.Further, L³ itself may be a double bond connecting C³ carbon atom and C⁴carbon atom. Also in this case, some of R⁴ through R¹¹ do/does not existin accordance with the existence of the double bond.

In the general formula (M-7), m1 and m2 each independently represent aninteger from 0 to 5. When m1 or m2 is no less than 2, there are aplurality of R¹⁴s or a plurality of R¹⁷s. Any two of such a plurality ofR¹⁴s or a plurality of R¹⁷s may be the same as each other or differentfrom each other, and may combine with each other to form a ringstructure.

In the general formula (M-7), n1 and n2 each independently represent 0or a positive integer, and are preferably 0, 1, 2 or 3, more preferably0, 1 or 2, and particularly preferably 0 or 1. When n 1 is no less than2, there are a plurality of R¹²s and a plurality of R¹³s. Any two ofsuch a plurality of R¹²s and a plurality of R¹³s may be the same as eachother or different from each other and may combine each other to form aring structure. When n2 is no less than 2, there are a plurality of R¹²sand a plurality of R¹³s. Any two of such a plurality of R¹⁵s and aplurality of R¹⁶s may be the same as or different from each other toform a ring structure. These may be the same each other or differentfrom each other or may combine with each other to form a ring structure.

In the general formula (M-7), L³ represents a divalent linkage groupthat, together with —C³—C¹—N¹—C²—C⁴—, forms a ring structure, a singlebond connecting C³ and C⁴, or a double bond connecting C³ and C⁴. As thedivalent linkage group, —O—, —S—, —N(R^(L1))—, and —C(R^(L2))(R^(L3))—is preferable. R^(L1) through R^(L3) are selected from the groupconsisting of a hydrogen atom or the substituents that can berepresented by R² or R³ in the general formula (M-1). R^(L1) throughR^(L3) each may be bonded to any one of R², R⁴ through R¹⁴ to form aring structure. When the bond between C³ and L³ or between C⁴ and L³ isa double bond, some of R^(L1) through R^(L3) do/does not exist inaccordance with the existence of the double bond.

In the general formula (M-7), two substituents which are selected fromR⁴ through R¹⁷ and R^(L1) through R^(L3) and are bonded to the same atommay be an identical atom or substituent so that a double bond is formed.(For instance, provided R⁴═R⁵═O, a carbonyl group (—CO—) may be formed.)

In the general formula (M-7), two substituents which are selected fromR⁴ through R¹⁷ and R^(L1) through R^(L3) and are bonded to atomsadjoining each other may be an identical atom or substituent so that a3-membered ring is formed. (For instance, provided R⁴═R⁸═O, an epoxygroup may be formed.)

Among the onium salts represented by the general formula (1-2), as afurther preferable example, an onium salt represented by the followinggeneral formula (1-2-A) can be cited.R^(A)—SO₃ ⁻M⁺  General formula (1-2-A):

In the general formula (1-2-A), R^(A) represents a substituent having atleast one substituent that has an alkali dissociative proton, and M⁺represents a counter cation selected from a sulfonium, iodonium,ammonium, phosphonium and oxonium.

As the substituent having an alkali dissociative proton on R^(A), aphenolic hydroxyl group (Ar—OH), a carboxyl group (—COOH), a mercaptogroup (—SH), a phosphonic acid group (—PO₃H₂), a phosphoric acid group(—OPO₃H₂), a sulfonamide group (—SO₂NH₂, —SO₂NHR), a substitutedsulfonamide type acidic group (hereinafter, referred to as “active imidegroup”. For example, —SO₂NHCOR, —SO₂NHSO₂R, or —CONHSO₂R), a sulfonicacid group (—SO₃H), a sulfinic acid group (—SO₂H), a —C(CF₃)₂OH, or a—COCH₂COCF₃ is preferable. In the above, Ar represents an aryl groupthat may have a substituent, and R represents a hydrocarbon group thatmay have a substituent. Furthermore, as examples each having anexcellent balance between the dissolution inhibiting effect and thesensitivity, a phenolic hydroxyl group, a carboxyl group, a mercaptogroup, a sulfonamide group, an active imide group, a —C(CF₃)₂OH and a—COCH₂COCF₃ can be cited. A phenolic hydroxyl group and a carboxyl groupare most preferable.

In R^(A), the skeleton having the substituent that has an alkalidissociative proton may be a hydrocarbon group that may have a furthersubstituent. Although there is no particular restriction on a structureof the hydrocarbon group, the hydrocarbon group preferably comprises anaromatic ring. The aromatic ring may be an aromatic hydrocarbon such asa benzene ring, a naphthalene ring, an anthracene ring, or aphenanthrene ring, or an aromatic heterocycle such as a pyrrole ring, apyridine ring, a quinoline ring, an acridine ring, an imidazole ring, afuran ring, a thiophene ring, and a thiazole ring. Among them, anaromatic hydrocarbon is preferable and a benzene ring is particularlypreferable.

In the general formula (1-2-A), M⁺ is preferably a sulfonium ion, aniodonium ion or a quaternary ammonium, in view of the dissolutioninhibiting effect. A quaternary ammonium ion is most preferable.Preferable examples of the quaternary ammonium ion are the quaternaryammonium ions cited as preferable examples in the explanation of thegeneral formula (1-2).

In the general formula (1-2), as a more preferable example, an oniumsalt represented by the following general formula (1-2-B) can be cited.Ar^(B)—SO₃ ⁻M⁺  General formula (1-2-B):

In the general formula (1-2-B), Ar^(B) represents an aryl group that hasat least one substituent having an alkali dissociative proton. M⁺represents a counter cation selected from a sulfonium ion, an iodoniumion, an ammonium ion, a phosphonium ion and an oxonium ion.

In the general formula (1-2-B), the substituent having an alkalidissociative proton is preferably a phenolic hydroxyl group (Ar—OH), acarboxyl group (—COOH), a mercapto group (—SH), a phosphonic acid group(—PO₃H₂), a phosphoric acid group (—OPO₃H₂), a sulfonamide group(—SO₂NH₂, —SO₂NHR), a substituted sulfonamide type acidic group(hereinafter, referred to as “active imide group”. For example,—SO₂NHCOR, —SO₂NHSO₂R, or —CONHSO₂R), a sulfonic acid group (—SO₃H), asulfinic acid group (—SO₂H), a —C(CF₃)₂OH, or a —COCH₂COCF₃ ispreferable. In the above, Ar represents an aryl group that may have asubstituent, and R represents a hydrocarbon group that may have asubstituent. As examples each having an excellent balance between thedissolution inhibiting effect and the sensitivity, a phenolic hydroxylgroup, a carboxyl group, a mercapto group, a sulfonamide group, anactive imide group, a —C(CF₃)₂OH and a —COCH₂COCF₃ can be cited. Aphenolic hydroxyl group and a carboxyl group are most preferable.

In the general formula (1-2-B), M⁺ is preferably a sulfonium ion, aniodonium ion and a quaternary ammonium ion, in view of the dissolutioninhibiting effect. A quaternary ammonium ion is most preferable.Preferable examples of the quaternary ammonium ion are the quaternaryammonium ions cited as preferable examples in the explanation of thegeneral formula (1-2).

Onium salts represented by the general formula (1-2) according to theinvention preferably does not have substantial absorption between from500 to 600 nm and more preferably does not have substantial absorptionin the visible light region.

One kind of the onium salt represented by the general formula (1-2) maybe used in the image forming material according to the invention.Alternatively, a plurality kinds of the onium salts represented by thegeneral formula (1-2) may be used in combination. A content of an oniumsalt represented by the general formula (1-2) is preferably 50% by massor less based on the whole solids content in the image forming layer,from the viewpoint of the film formability. In order to obtain excellentimage formability, the content of the onium salt is preferably in therange of from 0.1 to 30% by mass. Further, in order to satisfiessimultaneously the printing characteristics such as the press life andthe image formability at a high level, the content is most preferably inthe range of from 0.5 to 15%.

In the following, specific examples (exemplary compounds C-1 to C-30) ofthe onium salts that are preferably used in the invention andrepresented by the general formula (1-2) are cited. However, any oniumsalts represented by the general formula (1-2) can be selected and used,thus, the onium salts usable in the invention are not restricted to theexemplary compounds. TABLE 13 Comound No. Anion moiety Cation moiety C-1

C-2

C-3

C-4

C-5

C-6

TABLE 14 Compound No. Anion Moiety Cation Moiety C-7

C-8

C-9

C-10

C-11

TABLE 15 Compound No. Anion Moiety Cation Moiety C-12

C-13

C-14

C-15

C-16

C-17

C-18

TABLE 16 Compound No. Anion Moiety Cation Moiety C-19

C-20

C-21

C-22

C-23

C-24

C-25

TABLE 17 Compound No. Anion Moiety Cation Moiety C-26

C-27

C-28

C-29

C-30

In the following, a configuration common to both of the above-mentionedimage forming layers will be explained.

((B) Photo-Thermal Converting Agent)

An image forming layer according to the invention includes (B) aphoto-thermal converting agent.

The (B) photo-thermal converting agent used in the invention may be anysubstance that absorbs radiation for recording and generates heat,without particular restriction on an absorption wavelength regionthereof. However, from the viewpoint of suitability for exposure with aneasily available high power laser, an infrared light absorbing dye orpigment having the absorption maximum in wavelength region of 760 to1200 nm is preferable.

(Infrared Absorbing Dye or Pigment)

The dye used in the invention may be a commercially available dye or awell-known dye described in literatures such as The Society of SyntheticOrganic Chemistry, ed., Senryou Binran (Handbook of Dyes) (1970).Specific examples of the dye include azo dyes, metal complex azo dyes,pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes,phthalocyanine dyes, naphthalocyanine dyes, carbonium dyes, quinoniminedyes, methine dyes, cyanine dyes, squalirium dyes, (thio)pyrilium salts,metal-thiolate complexes, indoaniline metal complex dyes, oxonol dyes,diimonium dyes, aminium dyes, croconium dyes and inter-molecular type CTdyes.

Preferred examples include the cyanine dyes disclosed in JP-A Nos.58-125246, 59-84356, 59-202829, and 60-78787; the methine dyes disclosedin JP-A Nos. 58-173696, 58-181690, and 58-194595; the naphthoquinonedyes disclosed in JP-A Nos. 58-112793, 58-224793, 59-48187, 59-73996,60-52940, and 60-63744; the squarylium dyes disclosed in JP-A No.58-112792; and the cyanine dyes disclosed in BP No. 434,875.

Further, the near-infrared absorbing sensitizers disclosed in U.S. Pat.No. 5,156,938 can be preferably used. Furthermore, the substitutedarylbenzo(thio)pyrylium salts disclosed in U.S. Pat. No. 3,881,924: thetrimethine thiapyrylium salts disclosed in JP-A No. 57-142645(corresponding to U.S. Pat. No. 4,327,169); the pyrylium-based compoundsdisclosed in JP-A Nos. 58-181051, 58-220143, 59-41363, 59-84248,59-84249, 59-146063, and 59-146061; the cyanine dyes disclosed in JP-ANo. 59-216146; the pentamethine thiopyrilium salts disclosed in U.S.Pat. No. 4,283,475; and the pyrilium compounds disclosed in JP-B Nos.5-13514 and 5-19702 also can be preferably used.

Other preferable examples of the dye include near-infrared absorbingdyes represented by the formulas (I) and (II) in U.S. Pat. No.4,756,993.

Particularly preferable dyes among these dyes are cyanine dyes,phthalocyanine dyes, oxonol dyes, squarylium dyes, pyrylium salts,thiopyrilium dyes and nickel-thiolate complexes.

Dyes represented by the following general formulas (a) through (f) arepreferable because of excellent photo-thermal conversion efficiencythereof. In particular, when a cyanine dye represented by the followinggeneral formula (a) is used in the invention, the cyanine dye interactsstrongly with an alkali-soluble resin, and has excellent stability andeconomic efficiency. Accordingly, the cyanine dyes represented by thegeneral formula (a) are most preferable.

In the general formula (a), R¹ and R² each independently represent analkyl group having 1 to 12 carbon atoms, and the alkyl group may have asubstituent selected from an alkoxy group, an aryl group, an amidegroup, an alkoxycarbonyl group, a hydroxyl group, a sulfo group or acarboxyl group. Y¹ and Y² each independently represent an oxygen atom, asulfur atom, a selenium atom, a dialkylmethylene group or a —CH═CH—. Ar¹and Ar² each independently represent an aromatic hydrocarbon group andmay have a substituent selected from an alkyl group, an alkoxy group, ahalogen atom, or an alkoxy carbonyl group. In Ar¹, the carbon atomadjacent to Y¹ and a carbon atom adjacent to said carbon atom may belongto another ring that is condensed with Ar¹. In Ar², the carbon atomadjacent to Y² and a carbon atom adjacent to said carbon atom may bemembers of another ring that is condensed with Ar².

In the general formula (a), X represents a counter ion necessary forneutralizing an electric charge, which is not required when the cationmoiety of the dye has an anionic substituent. Q represents a polymethinegroup selected from a trimethine group, a pentamethine group, aheptamethine group, a nonamethine group or an undecamethine group. Fromthe viewpoints of the stability and wavelength aptitude for an infraredlight used for exposure, a pentamethine group, a heptamethine group or anonamethine group is preferable. From the viewpoint of the stability, Qpreferably comprises, in the methine chain thereof, three consecutivecarbon atoms that are members of a cyclohexene ring or a cyclopentenering.

In the general formula (a), Q may be substituted by a substituentselected from an alkoxy group, an aryloxy group, an alkylthio group, anarylthio group, a dialkylamino group, a diarylamino group, a halogenatom, an alkyl group, an aralkyl group, a cycloalkyl group, an arylgroup, an oxy group, an iminium group or a substituent represented bythe following general formula (i). As preferable substituents, halogenatoms such as a chlorine atom, diarylamino groups such as adiphenylamino group, and arylthio groups such as a phenylthio group canbe cited.

In the general formula (i), R³ and R⁴ each independently represent ahydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an arylgroup having 6 to 10 carbon atoms. Y³ represents an oxygen atom or asulfur atom.

When infrared light having a wavelength from 800 to 840 nm is used forexpose, heptamethine cyanine dyes represented by the following generalformulas (a-1) through (a-4) can be cited as particularly preferablyexamples among cyanine dyes represented by the general formula (a).

In the general formula (a-1), X¹ represents a hydrogen atom or a halogenatom. R¹ and R² each independently represent a hydrocarbon group having1 to 12 carbon atoms. In view of the storage stability of an imageforming layer coating solution, R¹ and R² each preferably represent ahydrocarbon group having 2 or more carbon atoms. R¹ and R² particularlypreferably combine with each other to form a 5- or 6-membered ring.

In the general formula (a-1), Ar¹ and Ar² may be the same as each otheror different from each other and each independently represent anaromatic hydrocarbon group that may have a substituent. The aromatichydrocarbon group is preferably a benzene ring or a naphthalene ring.The substituent on the aromatic hydrocarbon is preferably a hydrocarbongroup having 12 or less carbon atoms, a halogen atom, or an alkoxy grouphaving 12 or less carbon atoms. Y¹ and Y² may be the same as each otheror different from each other and each independently represent a sulfuratom or dialkyl methylene group having 12 or less carbon atoms. R³ andR⁴ may be the same as each other or different from each other and eachindependently represent a hydrocarbon group which has 20 or less carbonatoms and may have a substituent. The substituent is preferably analkoxy group having 12 or less carbon atoms, a carboxyl group or a sulfogroup. R⁵, R⁶, R⁷ and R⁸ may be the same as each other or different fromeach other and each independently represent a hydrogen atom orhydrocarbon group having 12 or less carbon atoms. From the viewpoint ofavailability of raw materials, R⁵, R⁶, R⁷ and R⁸ each preferablyrepresent a hydrogen. Za⁻ represents a counter anion necessary forneutralizing an electric charge. When the dye comprises an anionicsubstituent in its structure and there is no need of neutralizing anelectric charge, Za⁻ is not required. From the storage stability of arecording layer coating solution, Za⁻ preferably represents a halogenion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphateion or a sulfonic ion. Za⁻ particularly preferably represents aperchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion or asulfonic ion. Heptamethine dyes represented by the above general formula(a-1) can be preferably used in a positive image forming material, andcan be particularly preferably used in a so-called interaction removingtype positive photosensitive material, in which a photothermalconverting agent is combined with an alkali-soluble resin having aphenolic hydroxyl group.

In the general formula (a-2), R¹ and R² each independently represent ahydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. R¹ andR² may be bonded to each other to form a ring structure. The ringstructure is preferably a 5- or 6-membered ring, and particularlypreferably, a 5-membered ring. Ar¹ and Ar² may be the same as each otheror different from each other and each independently represent anaromatic hydrocarbon group that may have a substituent. The aromatichydrocarbon group is preferably a benzene ring or a naphthalene ring.The substituent on the aromatic hydrocarbon is preferably a hydrocarbongroup having 12 or less carbon atoms, a halogen atom, an alkoxy grouphaving 12 or less carbon atoms, an alkoxycarbonyl group, analkylsulfonyl group, or a halogenated alkyl group. The substituent onthe aromatic hydrocarbon is particularly preferably an electronattracting substituent. Y¹ and Y² may be the same as each other ordifferent from each other and each independently represent a sulfur atomor a dialkylmethylene group having 12 or less carbon atoms. R³ and R⁴may be the same as each other or different from each other and eachindependently represent a hydrocarbon group which has 20 or less carbonatoms and may have a substituent. The substituent on the hydrocarbon inR³ or R⁴ is preferably an alkoxy group having 12 or less carbon atoms, acarboxyl group, or a sulfo groups. R⁵, R⁶, R⁷ and R⁸ may be the same asone another or different from one another and each independentlyrepresent a hydrogen atom or a hydrocarbon group having 12 or lesscarbon atoms. From the viewpoint of availability of raw materials, R⁵,R⁶, R⁷ and R⁸ each preferably represent a hydrogen atom. R⁹ and R¹⁰ maybe the same as each other or different from each other. R⁹ and R¹⁰ eachindependently represent an aromatic hydrocarbon group having 6 to 10carbon atoms, an alkyl group having 1 to 8 carbon atoms, each of whichmay have a substituent, or a hydrogen atom, or R⁹ and R¹⁰ may combinewith each other to form the following rings.

R⁹ and R¹⁰ in the general formula (a-2) each particularly preferablyrepresent an aromatic hydrocarbon group such as a phenyl group.

X⁻ is a counter anion necessary for neutralizing an electric charge. Itsdefinition is the same as that of Za⁻ in the general formula (a-1).

In the general formula (a-3), R¹ through R⁸, Ar¹, Ar², Y¹, Y² and X⁻each have the same definition as that in the general formula (a-2). Ar³represents an aromatic hydrocarbon group such as a phenyl group and anaphthyl group, or a monocyclic or polycyclic heterocyclic ring eachcontaining at least one of a nitrogen atom, an oxygen atom and a sulfuratom. Ar³ represents preferably a heterocyclic ring selected from agroup consisting of a thiazole ring, a benzothiazole ring, anaphtothiazole ring, a thianaphtheno-7,6,4,5-thiazole ring, an oxazolering, a benzoxazole ring, a naphthoxazole ring, a selenazole ring, abenzoselenazole ring, a naphtoselenazole ring, a thiazoline ring, a2-quinoline ring, a 4-quinoline ring, a 1-isoquinoline ring, a3-isoquinoline ring, a benzimidazole ring, a 3,3-dialkylbenzindoleninering, a 2-pyridine ring, a 4-pyridine ring, a 3,3-dialkylbenz[e]indolering, a tetrazole ring, a triazole ring, a pyrimidine ring and athiadiazole ring. Ar³ represents particularly preferably a heterocyclicgroup having one of the following structures.

Ar³:

In the general formula (a-4), R¹ through R⁸, Ar¹, Ar², Y¹ and Y² eachhave the same definition as that in the above general formula (a-2). R¹¹and R¹² may be the same as each other or different from each other, andeach independently represent a hydrogen atom, an aryl group, acyclohexyl group or an alkyl group having 1 to 8 carbon atoms. Zrepresents an oxygen atom or a sulfur atom.

According to the invention, preferably examples of the cyanine dyerepresented by the general formula (a) include the following compounds,the compounds described in JP-A No. 2001-133969, paragraph Nos. [0017]to [0019], JP-A No. 2002-40638, paragraph Nos. [0012] to [0038] and JP-ANo. 2002-23360, paragraph Nos. [0012] to [0023].

In the general formula (b), L represents a methine chain having 7 ormore conjugate carbon atoms, and the methane chain may havesubstituent(s). If there are a plurality of substituents on the methinechain, the substituents may combine with each other to form a ringstructure. Zb⁺ represents a counter cation. Zb⁺ preferably represents anammonium ion, an iodonium ion, a sulfonium ion, a phosphonium ion, apyridium ion, or an alkali metal cation (Na⁺, K⁺, or Li⁺). R⁹ throughR¹⁴ and R¹⁵ through R²⁰ each independently represent a hydrogen atom ora substituent selected from a halogen atom, a cyano group, an alkylgroup, an aryl group, an alkenyl group, an alkynyl group, a carbonylgroup, a thio group, a sulfonyl group, a sulfinyl group, an oxy groupand an amino group, or a substituent obtained by combining two or threeof these substituents. Any two of R⁹ through R¹⁴ and R¹⁵ through R²⁰ maycombine with each other to form a ring structure. Among the compoundsrepresented by the general formula (b), compounds in which L representsa methine chain comprising 7 conjugate carbon atoms, and compounds inwhich all of R⁹ through R¹⁴ and R¹⁵ through R²⁰ represent hydrogen atomsare preferable from the viewpoint of availability and effect thereof.

In the invention, as preferable examples of dyes represented by thegeneral formula (b), the dyes exemplified below can be cited.

In the general formula (c), Y³ and Y⁴ each independently represent anoxygen atom, a sulfur atom, a selenium atom or a tellurium atom. Mrepresents a methine chain comprising 5 or more conjugate carbon atoms.R²¹ through R²⁴ and R²⁵ through R²⁸ may be the same as each other ordifferent from each other. R²¹ through R²⁴ and R²⁵ through R²⁸ eachindependently represent a hydrogen atom, a halogen atom, a cyano group,an alkyl group, an aryl group, an alkenyl group, an alkynyl group, acarbonyl group, a thio group, a sulfonyl group, a sulfinyl group, an oxygroup or an amino group. In the general formula (c), Za⁻ represents acounter anion and has the same definition as that of Za⁻ in the generalformula (a-1).

In the invention, as preferable examples of dyes represented by thegeneral formula (c), the dyes exemplified below can be cited.

In the general formula (d), R²⁹ through R³² each independently representa hydrogen atom, an alkyl group, or an aryl group. R³³ and R³⁴ eachindependently represent an alkyl group, a substituted oxy group, or ahalogen atom. In the general formula (d), n and m each independentlyrepresent an integer from 0 to 4. R²⁹ and R³⁰, or R³¹ and R³² maycombine with each other to form a ring. R²⁹ and/or R³⁰ may combine withR³³ to form a ring. R³¹ and/or R³² may combine with R³⁴ to form a ring.When there are a plurality of R³³s, any two of such a plurality of R³³smay combine with each other to form a ring. When there are a pluralityof R³⁴s, any two of such a plurality of R³⁴s may combine with each otherto form a ring. X² and X³ each independently represent a hydrogen atom,an alkyl group, or an aryl group. Q represents a trimethine group whichmay have a substituent or a pentamethine group which may have asubstituent, and, together with a divalent organic group, may form aring structure. Zc⁻ represents a counter anion and has the samedefinition as that of Za⁻ in the general formula (a-1).

In the invention, as preferable examples of dyes represented by thegeneral formula (d), the dyes exemplified below can be cited.

In the general formula (e), R³⁵ through R⁵⁰ each independently representa hydrogen atom, a halogen atom, a cyano group, an alkyl group, an arylgroup, an alkenyl group, an alkynyl group, a hydroxyl group, a carbonylgroup, a thio group, a sulfonyl group, a sulfinyl group, an oxy group,an amino group or an onium salt structure, all of which may have asubstituent. M represents two hydrogen atoms or a metal atom, ahalometal group, or an oxymetal group. As the metal contained therein,IA, IIA, IIIB and IVB group atoms, first, second and third periodtransition metals, and lanthanide elements in the periodic table can becited. Among these metals, copper, nickel, magnesium, iron, zinc, tin,cobalt, aluminum, titanium, and vanadium are preferable. Vanadium,nickel, zinc and tin are particularly preferable. These metal atoms eachmay combine with an oxygen atom, a halogen atom, or the like to satisfyits valence number.

In the invention, preferable examples of the dye represented by thegeneral formula (e) include the dyes exemplified below.

In the general formulas (f-1) and (f-2), R⁵¹ through R⁵⁸ eachindependently represent a hydrogen atom, an alkyl group which may have asubstituent, or an aryl group which may have a substituent. X⁻ has thesame definition as that in the above general formula (a-2).

In the invention, preferable examples of the dye represented by thegeneral formula (d) include the dyes exemplified below.

As photo-thermal converting agents other than the above-cited examples,the dyes which have a plurality of chromophoric groups and are describedin JP-A No. 2001-242613, the dyes which each have a chromophoric groupcovalently linked to a polymer compound and are described in JP-A No.2002-97384 and U.S. Pat. No. 6,124,425, the anionic dyes described inU.S. Pat. No. 6,248,893, and the dyes that each have a surface orientinggroup and are described in JP-A No. 2001-347765 can be preferably used.

As pigments that can be used as a photo-thermal converting agent in theinvention, commercially available pigments and pigments described in“Color Index (C. I.) Handbook”, Nippon ganryou gijutsu kyoukai ed.,Saishin ganryou binran (Current Pigment Handbook, 1977), Saishin ganryououyou gijutsu (Current Pigment Application Technology) (CMC, 1986), andInsatsu inki gijutsu (Printing Ink Technology) (CMC, 1984) can be cited.

Examples of kinds of the pigments include black pigments, yellowpigments, orange pigments, brown pigments, red pigments, violetpigments, blue pigments, green pigments, fluorescent pigments, metalpowder pigments, and polymer bonding pigments. Specifically, insolubleazo pigments, azo-lake pigments, condensed azo pigments, chelate azopigments, phthalocyanine pigments, anthraquinone pigments, perylenepigments, perinone pigments, thioindigo pigments, quinacridone pigments,dioxazine pigments, isoindolinone pigments, quinophthalone pigments,dyeing lake pigments, azine pigments, nitroso pigments, nitro pigments,natural pigments, inorganic pigments and carbon black can be used. Amongthem, carbon black is preferable.

These pigments may be used after or without being subjected to a surfacetreatment. The surface treatment may be conducted by a method such as amethod of coating the surface of the pigment with a resin or wax, amethod of adhering a surfactant to the surface, an a method of combininga reactive substance (for example, a silane coupling agent, an epoxycompound, or a polyisocyanate) with the surface of the pigment. Theabove-mentioned surface treatment methods are described in Kinzokusekken no seishitsu to Ouyou (Properties of Metallic Soaps and theirApplications) (Saiwai Shobou), Insatsu Inki Gijutsu (Printing InkTechnology) (CMC, 1984), and Saishin ganryou ouyou gijutsu (CurrentPigment Application Technology) (CMC, 1986).

The particle diameter of the pigment is preferably in the range of from0.01 to 10 μm, more preferably from 0.05 to 1 μm, and particularlypreferably from 0.1 to 1 μm. When the particle diameter of the pigmentis less than 0.01 μm, the stability of the material dispersed in animage forming layer coating solution is unsatisfactory, and when theparticle diameter is greater than 10 μm, the uniformity of the imageforming layer is unsatisfactory.

As the method for dispersing the pigment, a known dispersing technologythat is used in production of ink, toner or the like can be used.Examples of the dispersing machine include an ultrasonic disperser, asand mill, an attriter, a pearl mill, a super mill, a ball mill, animpeller, a disperser, a KD mill, a colloid mill, a dynatron, a threeroll mill, and a press kneader. The details thereof are described inSaishin ganryou Ouyou gijutsu (Current Pigment Application Technology)(CMC, 1986).

The pigment or the dye can be added in an amount of 0.01 to 50% by mass,preferably 0.1 to 10% by mass, based on the total mass of all solidscontent of the image forming layer (recording layer). In the case of adye, an amount of 0.5 to 10% by mass is particularly preferable. In thecase of a pigment, an amount of 0.1 to 10% by mass is particularlypreferable. When an amount of the pigment or dye added is less than0.01% by mass, the sensitivity tends to decrease. When the amount ismore than 50% by mass, with an increase of an amount compounded, theuniformity of the recording layer is lost, and durability of therecording layer may be deteriorated. Single kind of dye or pigment maybe used or a multiple kinds of dyes or pigments may be used incombination. In order to support exposure machines each having adifferent wavelength, dyes or pigments each having a differentabsorption wavelength can be preferably used in combination.

(Other Components)

When the positive image forming layer according to the invention isformed, in accordance with necessity, an additive can be further added.It is preferable, from the viewpoint of improving the effect ofinhibiting an image portion from being dissolved by a developer, to usea substance that is thermally decomposable and substantially reduces thesolubility of the alkaline water-soluble polymer compound in the intactstate. Examples of such a substance include other onium salts,o-quinonediazide compounds, aromatic sulfone compounds, and aromaticsulfonic acid esters. Such other onium salts are, in the case of thefirst image forming layer according to the invention, onium salts otherthan the onium salts represented by the general formula (1-1). In thecase of the second image forming layer according to the invention, suchother onium salts are onium salts other than the onium salts representedby the general formula (1-2). Examples of the other onium salt includediazonium salts, ammonium salts, phosphonium salts, iodonium salts,sulfonium salts, selenonium salts, arsonium salts and azinium salts.

Preferable examples of the other onium salts used in the inventioninclude the diazonium salts described in S. I. Schlesinger, “Photogr.Sci. Eng.”, 18 (1974), 387, T. S. Bal et al., “Polymer”, 21 (1980), 423and JP-A No. 5-158230; the ammonium salts described in U.S. Pat. Nos.4,069,055 and 4,069,056, and JP-A No. 3-140140; the phosphonium saltsdescribed in D. C. Necker et al., “Macromolecules”, 17 (1984), 2468, C.S. Wen et al, “Teh, Proc. Conf. Rad. Curing ASIA”, Tokyo, October(1988), p. 478, and U.S. Pat. Nos. 4,069,055 and 4,069,056; the iodoniumsalts described in J. V. Crivello et al., “Macromolecules”, 10(6),(1977) 1307, “Chem. & Eng. News”, Nov. 28 (1988), p. 31, EP Patent No.104,143, U.S. Pat. Nos. 5,041,358 and 4,491,628 and JP-A Nos. 2-150848and 2-296514; the sulfonium salts described in J. V. Crivello et al,“Polymer J.” 17 (1985), 73, J. V. Crivello et al, “J. Org. Chem.”, 43(1978), 3055, W. R. Watt et al, “J. Polymer Sci.”, “Polymer Chem. Ed.”,22 (1984), 1789, J. V. Crivello et al, “Polymer Bull.”, 14 (1985), 279,J. V. Crivello et al, “Macromolecules”, 14(5) (1981), 1141, J. V.Crivello et al, “J. Polymer Sci.”, “Polymer Chem. Ed.”, 17 (1979), 2877,EP Patent Nos. 370,693, 233,567, 297,443 and 297,442, U.S. Pat. Nos.4,933,377, 3,902,114, 5,041,358, 4,491,628, 4,760,013, 4,734,444 and2,833,827, DE Patent Nos. 2,904,626, 3,604,580 and 3,604,581; theselenonium salts described in J. V. Crivello et al, “Macromolecules”,10(6) (1977), 1307, and J. V. Crivello et al, “J. Polymer Sci.”,“Polymer Chem. Ed.”, 17 (1979), 1047; and the arsonium salts describedin C. S. Wen et al, “Teh, Proc. Conf. Rad. Curing ASIA”, p. 478 Tokyo,October (1988), and the like.

Among other onium salts, diazonium salts are particularly preferable.Furthermore, as particularly preferable diazonium salts, the compoundsdescribed in JP-A No. 5-158230 can be cited.

Examples of the counter ion in the other onium salt includetetrafluoroboric acid, hexafluorophosphoric acid,triisopropylnaphthalene sulfonic acid, 5-nitro-o-toluene sulfonic acid,5-sulfosalicylic acid, 2,5-dimethylbenzene sulfonic acid,2,4,6-trimethylbenzene sulfonic acid, 2-nitrobenzene sulfonic acid,3-chlorobenzene sulfonic acid, 3-bromobenzene sulfonic acid,2-fluorocaprylnaphthalene sulfonic acid, dodecylbenzene sulfonic acid,1-naphthol-5-sulfonic acid, 2-methoxy-4-hydroxy-5-benzoyl-benzenesulfonic acid, and p-toluene sulfonic acid. Among them,hexafluorophosphoric acid, and alkylaromatic sulfonic acids such astriisopropylnaphthlene sulfonic acid and 2,5-dimethylbenzene sulfonicacid are particularly preferable.

As preferable quinonediazides, o-quinonediazide compounds can be cited.The o-quinonediazide compound used in the invention is a compound thathas at least one o-quinonediazide group and increases thealkali-solubility thereof owing to thermal decomposition, ando-quinonediazide compounds of various structures can be used. That is,o-quinonediazide helps the dissolution of a photosensitive materialsince, when the o-quinonediazide is thermally decomposed, theo-quinonediazide ceases to inhibit a binder from being dissolved and theo-quinonediazide itself transforms to alkali-soluble substance. Examplesof the o-quinonediazide compound usable in the invention include thecompounds described in J. Coser Light-sensitive Systems (John Wiley &Sons. Inc.), pp. 339 to 352. Particularly preferable examples of theo-quinonediazide include sulfonic acid esters or sulfonic acid amides ofo-quinonediazide obtained by reacting o-quinonediazindes with variousaromatic polyhydroxy compounds or aromatic amino compounds. An ester ofbenzoquinone-(1,2)-diazidesulfonic acid chloride ornaphthoquinone-(1,2)-diazide-5-sulfonic acid chloride with apyrogallol-acetone resin as described in JP-B No. 43-28403, or an esterof benzoquinone-(1,2)-diazidesulfonic acid chloride ornaphthoquinone-(1,2)-diazide-5-sulfonic acid chloride with aphenol-formaldehyde resin as described in U.S. Pat. Nos. 3,046,120 and3,188,210 can also be suitably used.

An ester of naphthoquinone-(1,2)-diazide-4-sulfonic acid chloride with aphenol-formaldehyde resin or a cresol-formaldehyde resin, and an esterof naphthoquinone-(1,2)-diazide-4-sulfonic acid chloride with apyrogallol-acetone resin can also be suitably used. Other usefulo-quinonediazide compounds are known and reported in a number ofpatents. For example, o-quinonediazide compounds described in JP-A Nos.47-5303, 48-63802, 48-63803, 48-96575, 49-38701 and 48-13354, JP-B Nos.41-11222, 45-9610 and 49-17481, U.S. Pat. Nos. 2,797,213, 3,454,400,3,544,323, 3,573,917, 3,674,495 and 3,785,825, U.K. Patent Nos.1,227,602, 1,251,345, 1,267,005, 1,329,888 and 1,330,932, and Germanpatent DE 854,890 can be used.

An amount of the o-quinonediazide compound added is preferably from 1 to50% by mass, more preferably from 5 to 30% by mass, and particularlypreferably from 10 to 30% by mass, based on the total solids content ofthe image forming material. Single kind of o-quinonediazide compound canbe used, or a multiple kinds of o-quinonediazide compounds can be usedin combination.

An addition amount of an additive other than the o-quinonediazidecompound is preferably from 1 to 50% by mass, more preferably from 5 to30% by mass, and particularly preferably from 10 to 30% by mass, basedon the total solids content of the image forming material. An additiveand a binder used in the invention are preferably contained in the samelayer.

In order to improve sensitivity further, a cyclic acid anhydride, aphenol and an organic acid can be further used. The cyclic acidanhydride may be a phthalic anhydride, a tetrahydrophthalic anhydride, ahexahydrophthalic anhydride, a 3,6-endooxy-Δ4-tetrahydrophthalicanhydride, tetrachlorophthalic anhydride, maleic anhydride, chloromaleicanhydride, α-phenylmaleic anhydride, succinic anhydride, or pyromelliticanhydride, all of which are described in U.S. Pat. No. 4,115,128.Examples of the phenol include bisphenol A, p-nitrophenol,p-ethoxyphenol, 2,4,4′-trihydroxybenzophenone,2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone,4,4′,4″-trihydroxytriphenylmethane, and 4,4′,3″,4″-tetrahydroxy-3,5,3′,5′-tetramethyltriphenylmethane. Examples of theorganic acid include the sulfonic acids, the sulfinic acids, thealkylsulfuric acids, the phosphonic acids, the phosphoric acid esters,and the carboxylic acids described in JP-A Nos. 60-88942 and 2-96755.Specific examples the organic acid include p-toluene sulfonic acid,dodecylbenzene sulfonic acid, p-toluene sulfinic acid, ethylsulfuricacid, phenylphosphonic acid, phenylphophinic acid, phenyl phosphate,diphenyl phosphate, benzoic acid, isophthalic acid, adipic acid,p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalicacid, 4-cyclohexene-1,2-dicarboxylic acid, erucic acid, lauric acid,n-undecanoic acid, and ascorbic acid. A total proportion of theabove-mentioned cyclic acid anhydrides, phenols and organic acids in animage forming material is preferably from 0.05 to 20% by mass, morepreferably from 0.1 to 15% by mass, and particularly preferably from 0.1to 10% by mass.

In an image forming layer coating solution in the invention, in order toensure stability of development under broader variety of developmentconditions, it is possible to add at least one of nonionic surfactantssuch as ones described in JP-A Nos. 62-251740 and 3-208514, amphotericsurfactants such as ones described in JP-A Nos. 59-121044 and 4-13149,siloxane-based compounds such as ones described in EP No. 950517, andfluorine-containing monomer copolymers such as ones described in JP-ANo. 11-288093.

Specific examples of the nonionic surfactant include sorbitantristearate, sorbitan monopalmitate, sorbitan trioleate, monostearin,and polyoxyethylene nonylphenyl ether. Specific examples of theamphoteric surfactant include alkyldi(aminoethyl)glycine,alkylpolyaminoethylglycine hydrochloride,2-alkyl-N-carboxyethyl-N-hydroxyethyl imidazolynium betaine, andN-tetradecyl-N,N-betaine type surfactant (for example, trade name“AMOGEN K”, manufactured by Dai-ichi Kogyo Corporation.).

As the siloxane-based compound, a block copolymer of dimethylsiloxaneand polyalkylene oxide is preferable, and specific examples thereofinclude polyalkylene oxide modified silicones such as DBE-224, DBE-621,DBE-712, DBP-732 and DBP-534 manufactured by Chisso Corporation, TEGOGLIDE 100 manufactured by Tego Corporation (Germany).

A total proportion of the above-mentioned nonionic surfactants and theamphoteric surfactants in an image forming material is preferably from0.05 to 15% by mass, and more preferably from 0.1 to 5% by mass.

The image forming layer according to the invention may comprise aprinting-out agent for obtaining a visible image immediately afterheating by exposure, or a dye or pigment as an image coloring agent.

A combination of a compound (light acid releasing agent) that release anacid owing to heat which is generated by exposure and an organic dyecapable of forming a salt is a typical example of the print-out agent.Specific examples of the combination include a combination ofo-naphthoquinonediazide-4-sulfonic acid halogenide and a salt-formingorganic dye described in JP-A Nos. 50-36209 and 53-8128, and acombination of a trihalomethyl compound and a salt-forming organic dyedescribed in JP-A Nos. 53-36223, 54-74728, 60-3626, 61-143748, 61-151644and 63-58440. Examples of the trihalomethyl compound includeoxazole-based compounds and triazine-based compounds. Both types ofcompounds have excellent temporal stability and give clear print-outimage.

As the image coloring agent, a dye other than the above-mentionedsalt-forming organic dyes can also be used. An oil-soluble dye or abasic dye is preferably used as such another dye or the salt-formingorganic dye. Specific examples thereof include OIL YELLOW #101, OILYELLOW #103, OIL PINK #312, OIL GREEN BG, OIL BLUE BOS, OIL BLUE #603,OIL BLACK BY, OIL BLACK BS, OIL BLACK T-505 (all of these aremanufactured by Orient Chemical Industries, Ltd.), Victoria Pure Blue,Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet,Rhodamine B (CI145170B), Malachite Green (CI42000) and Methylene Blue(CI52015). The dyes described in JP-A No. 62-293247 are particularlypreferable. These dyes can be added in an image forming material in anamount of 0.01 to 10% by mass, and preferably 0.1 to 3% by mass based onthe total solids content of the image forming material. In accordancewith necessity, a plasticizer is added to an image forming materialaccording to the invention to provide a film with flexibility. Examplesof the plasticizer include oligomers and polymers of butylphthalyl,polyethylene glycol, tributyl citrate, diethyl phthalate, dibutylphthalate, dihexyl phthalate, dioctyl phthalate, tricresyl phosphate,tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate,acrylic acid, and methacrylic acid.

Further, epoxy compounds, vinyl ethers, the phenol compounds each havinga hydroxymethyl group described in JP-A No. 8-276558, phenol compoundseach having an alkoxymethyl group, and the cross-linking compoundshaving alkali-dissolution inhibiting effect described in JP-A No.11-160860, which has been proposed by the present inventors, can beappropriately added in accordance with an object.

The image forming material according to the invention, which is formedby forming an image forming layer on a suitable substrate, can be usedfor various applications such as a planographic printing plateprecursor, color proof, and display material. The image forming materialaccording to the invention is particularly useful as a heat-mode typeplanographic printing plate precursor that can be subjected to directplate-making with infrared laser exposure.

(Planographic Printing Plate Precursor)

In the following, specific examples will be explained with examples inwhich an image forming material according to the invention is used as aplanographic printing plate precursor.

(Image Forming Layer)

A planographic printing plate precursor utilizing the image formingmaterial according to the invention can be produced by dissolvingingredients of a photosensitive layer (image forming layer) coatingsolution in a solvent followed by coating the obtained photosensitivelayer coating solution on a suitable substrate. In addition, inaccordance with an object, a protective layer, a resin intermediatelayer, a back coat layer, or the like can be provided in a similarmanner.

Example of the solvent include, but are not limited to, ethylenedichloride, cyclohexanone, methyl ethyl ketone, methanol, ethanol,propanol, ethylene glycol monomethyl ether, 1-methoxy-2-propanol,2-methoxyethyl acetate, 1-methoxy-2-propyl acetate, dimethoxyethane,methyl lactate, ethyl lactate, N,N-dimethylacetamide,N,N-dimethylformamide, tetramethylurea, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, γ-butyrolactone and toluene. A single kind ofsolvent may be used or a plurality kinds of solvents may be used incombination.

A concentration of the above components (a total solids contentincluding additives) in the solvent is preferably in the range of from 1to 50% by mass.

A coated amount (solids content) on the substrate after coating anddrying varies based on applications of the image forming layer. In thecase of an image forming layer of a planographic printing plateprecursor, the coated amount is generally preferably in the range offrom 0.5 to 5.0 g/m². As the coated amount becomes smaller, apparentsensitivity becomes larger, however the film characteristics of theimage forming layer deteriorate.

Further, a single image forming layer may be provided, or a multipleimage forming layers may be provided.

Various coating methods can be employed. For instance, bar coatercoating, rotary coating, spray coating, curtain coating, dip coating,air knife coating, blade coating and roll coating can be cited.

In order to improve coating properties, the image forming layeraccording to the invention may contain a surfactant such as afluorine-type surfactant described in JP-A No. 62-170950. An additionamount is preferably in the range of from 0.01 to 1% by mass and morepreferably from 0.05 to 0.5% by mass relative to a total solids contentin the image forming layer.

(Resin Intermediate Layer)

In the planographic printing plate precursor according to the invention,a resin intermediate layer may be provided between an image forminglayer and a substrate in accordance with necessity.

When a resin intermediate layer is provided, the image forming layerwhose solubility in an alkali developer increases by exposure to aninfrared radiation is still on the exposure surface or close to theexposure surface, and has good sensitivity to an infrared laser beam. Aresin intermediate layer made of a polymer provided between a substrateand an image forming layer functions as a heat-insulating layer so thatheat generated by exposure to an infrared laser beam is not diffused tothe substrate and used efficiently for formation of image, therebyattaining higher sensitivity. It is considered that in an unexposedportion, since the image forming layer, which is impermeable to analkali developer, functions as a layer protecting the resin intermediatelayer, development stability is improved. Therefore, an image havingexcellent discrimination is formed, and a periodical stability isensured. On the other hand, in an exposed portion, the component of theimage forming layer, which are no longer inhibited from dissolving in analkali developer, readily dissolve and disperse in the developer.Further, since the resin intermediate layer, which is made of analkali-soluble polymer, has a high solubility in the developer, theintermediate layer dissolves in the developer well. Accordingly, evenwhen a developer having a decreased activity is used, an image portiondissolves quickly without leaving a residual film. In this way anintermediate layer contributes also to improve developability. For thereasons recited above, it is considered that the resin intermediatelayer is useful.

(Substrate)

Examples of the substrate that can be used in the invention includedimensionally stable plate materials, such as paper, paper laminatedwith plastic (such as polyethylene, polypropylene and polystyrene),metal plates (such as aluminum, zinc and copper), plastic films (such ascellulose diacetate, cellulose triacetate, cellulose propionate,cellulose butyrate, cellulose acetate butyrate, cellulose nitrate,polyethylene terephthalate, polyethylene, polystyrene, polypropylene,polycarbonate and polyvinylacetal), paper or plastic films laminatedwith or metallized with metals such as the above metals.

The substrate according to the invention is preferably a polyester filmor an aluminum plate particularly when it is used in a planographicprinting plate precursor. Among these materials, an aluminum plate,which has high dimensional stability and is relatively inexpensive, isparticularly preferable. A preferable aluminum plate is a pure aluminumplate, an alloy plate containing aluminum as a major component and traceamount(s) of foreign element(s), or a plastic film laminated with ormetallized with aluminum. Examples of foreign elements contained in thealuminum alloy include silicon, iron, manganese, copper, magnesium,chromium, zinc, bismuth, nickel and titanium. A total content of theseforeign elements in the alloy is no more than 10% by mass. Particularlypreferable aluminum in the invention is pure aluminum. However, since itis difficult to produce perfectly pure aluminum from the viewpoint ofrefining technology, the aluminum plate may contain trace foreignelements.

As aforementioned, the composition of the aluminum plate used in theinvention is not specified, and aluminum plates which have been wellknown or commonly used may be used appropriately. A thickness of thealuminum plate used in the invention is substantially from 0.1 to 0.6mm, preferably from 0.15 to 0.4 mm and particularly preferably from 0.2to 0.3 mm.

Prior to roughing an aluminum plate, in accordance with necessity,degreasing treatment with, for instance, a surfactant, an organicsolvent, or an aqueous alkaline solution is carried out to removerolling oil on the surface. The surface roughing treatment of thesurface of the aluminum plate is carried out by any of various methods.For example, the surface roughing treatment is carried out bymechanically roughening surface, by electrochemically dissolving androughening a surface, or by dissolving a surface chemically andselectively. As the mechanical methods, known methods such as ballpolishing methods, brush polishing methods, blast polishing methods andbuff polishing methods may be used. Further, as the electrochemicalsurface roughing method, a surface may be roughened with alternatingcurrent or direct current in a hydrochloric acid or nitric acidelectrolytic solution. Also, as disclosed in JP-A No. 54-63902, a methodin which both the mechanical surface-roughening and the electrochemicalsurface-roughening are combined may be employed. Thus surface roughenedaluminum plate is, in accordance with necessity, subjected to an alkalietching and a neutralizing treatment, and thereafter, optionally,subjected to an anodic oxidation treatment in order to improve themoisture retention and wear resistance of the surface. The electrolyteused for the anodic oxidation treatment of the aluminum plate isselected from the various electrolytes that form a porous oxidationfilm. The electrolyte may be, generally, sulfuric acid, phosphoric acid,oxalic acid, chromic acid or a mixture thereof. A concentration of theelectrolyte is appropriately determined based on the kind of theelectrolyte.

The treating conditions of the anodic oxidation cannot be uniquelyspecified because a suitable condition varies based on the kind of theelectrolyte. However, in general, regarding the anodic oxidationconditions, it is suitable that a concentration of the electrolyteshould be from 1 to 80% by mass in the solution, a solution temperatureshould be 5 to 70 degree centigrade, a current density should be from 5to 60 A/dm², a voltage should be from 1 to 100 V, and an electrolyzationtime should be from 10 seconds to 5 minutes. When an amount of theanodic oxidation film is less than 1.0 g/m², press life is insufficientand a non-image portion of the planographic printing plate tends to bescarred. Hence, a so-called “scar-stain”, that is, an adherence of inkto a scar during printing, tends to occur. After the anodic oxidationtreatment is conducted, the surface of the aluminum plate may beoptionally subjected to a hydrophilicity-imparting treatment. The methodfor imparting hydrophilicity to the aluminum surface may be selectedfrom an alkali metal silicate (for instance, aqueous sodium silicatesolution) method such as the methods described in U.S. Pat. Nos.2,714,066, 3,181,461, 3,280,734 and 3,902,734. In this method, thesubstrate is dipped or electrolytically treated in an aqueous sodiumsilicate solution. Alternatively, a method in which the substrate istreated with potassium fluorozirconate disclosed in JP-B No. 36-22063 ora method in which the substrate is treated with polyvinylphosphonic aciddisclosed in U.S. Pat. No. 3,276,868, 4,153,461 or 4,689,272 can beused.

In the planographic printing plate precursor according to the invention,a positive-type image forming layer is provided on a substrate; however,in accordance with necessity, an undercoat layer may be disposed betweenthe positive-type image forming layer and the substrate.

Various organic compounds can be used as the components for theundercoat layer. The undercoat layer may include an organic compoundselected from, for example, carboxymethyl cellulose; dextrin; gumarabic; phosphonic acids having an amino group, such as2-aminoethylphosphonic acid; organic phosphonic acids such asphenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid,glycerophosphonic acid, methylenediphosphonic acid andethylenediphosphonic acid, all of which may have a substituent; organicphosphoric acids such as phenylphosphoric acid, naphthylphosphoric acid,alkylphosphoric acid and glycerophosphoric acid, all of which may have asubstituent; organic phosphinic acids such as phenylphosphinic acid,naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinicacid, all of which may have a substituent; amino acids such as glycineand β-alanine; and hydrochlorides of amines each having a hydroxylgroup, such as hydrochloride of triethanolamine. Two or more of thesecompounds may be used in combination.

The organic undercoat layer may be provided by the following method.That is, a solution obtained by dissolving component(s) of the undercoatlayer in water or an organic solvent such as methanol, ethanol or methylethyl ketone or a mixture solvent thereof is coated on the aluminumplate and dried to form an undercoat layer. Alternatively the organicunder coat layer may be provided by a method in which the aluminum plateis dipped in a solution obtained by dissolving component(s) in water oran organic solvent such as methanol, ethanol and methyl ethyl ketone ora mixture solvent thereof to allow the components to be adsorbed by thealuminum plate, followed by washing with water or the like and by dryingto form an organic undercoat layer. In the former method, a solutioncontaining the organic compound (component of the undercoat layer) in anamount of 0.005 to 10% by mass may be applied by any one of variousmethods.

Furthermore, in the latter method, a concentration of the solution isfrom 0.01 to 20% by mass and preferably from 0.05 to 5% by mass; adipping temperature is from 20 to 90° C. and preferably from 25 to 50°C.; and a dipping time is from 0.1 seconds to 20 minutes and preferablyfrom 2 seconds to 1 minute. A pH of the solution may be adjusted in thepH range of 1 to 12 by using a basic material such as ammonia,triethylamine or potassium hydroxide or an acidic material such ashydrochloric acid or phosphoric acid. Further, a yellow dye may be addedto improve tone reproducibility of the image recording material.

A coated amount of the organic undercoat layer is properly from 2 to 200mg/m² and preferably 5 to 100 mg/m². When the above coating amount isless than 2 mg/m², a sufficient press life is not obtained. Also whenthe coating amount is greater than 200 mg/m², a sufficient press life isnot obtained.

(Exposure Development)

The positive planographic printing plate precursor obtained above isusually subjected to an image-wise exposure process and a developingprocess.

A light source of beam of rays used in the image-wise exposure processhas an emission wavelength preferably in a range from the near-infraredregion to the infrared region. The light source is particularlypreferably a solid laser or a semiconductor laser.

As a developer and a replenisher of the planographic printing plateprecursor according to the invention, a conventionally known aqueousalkali solution can be used.

Examples of the alkali include inorganic alkali salts such as sodiumsilicate, potassium silicate, sodium tertiary phosphate, potassiumtertiary phosphate, ammonium tertiary phosphate, sodium secondaryphosphate, potassium secondary phosphate, ammonium secondary phosphate,sodium carbonate, potassium carbonate, ammonium carbonate, sodiumhydrogen carbonate, potassium hydrogen carbonate, ammonium hydrogencarbonate, sodium borate, potassium borate, ammonium borate, sodiumhydroxide, ammonium hydroxide, potassium hydroxide and lithiumhydroxide. Alternatively, organic alkali agents such as monomethylamine,dimethylamine, trimethylamine, monoethylamine, diethylamine,triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine,n-butylamine, monoethanolamine, diethanolamine, triethanolamine,monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamineand pyridine may be used. A single alkali agent may be used or amultiple alkali agents may be used in combination.

Particularly preferable developers are aqueous solutions of silicatessuch as sodium silicate and potassium silicate. This is because thedevelopability can be controlled by changing concentrations of siliconoxide SiO₂, which is a component of a silicate, and an alkali metaloxide M₂O, and by changing a ratio between the SiO₂ and the M₂O. Alkalimetal silicates such as the alkali metal silicates described in JP-A No.54-62004 and JP-B No. 57-7427 may be used effectively.

When an automatic processor is used in the development, it is knownthat, by adding an aqueous solution (replenisher) having higheralkalinity than a developer to the developer, a large number ofplanographic printing plate precursors can be developed withoutexchanging the developer in a developing tank for a long period of time.This replenishing system is also preferable in the invention.

Various surfactants or organic solvents may be optionally added to adeveloper and a replenisher with the intention of promoting orsuppressing developability, dispersing developing refuse and improvingaffinity of an image portion on the printing plate to ink.

Preferable examples of the surfactant include anionic, cationic,nonionic and amphoteric surfactants. In accordance with necessity, areducing agent such as a sodium salt or a potassium salt of an inorganicacid such as hydroquinone, resorcinol, sulfurous acid, orhydrogensulfurous acid; an organic carboxylic acid; an antifoamingagent; or a water softener may be further added to a developer or to areplenisher.

The printing plate that has been developed with the foregoing developerand replenisher is subjected to post-treatment with rinsing water, arinsing solution containing a surfactant or the like, or a desensitizingsolution containing gum arabic or a starch derivative. These treatmentsmay be variously combined and used in the post-treatment when the imagerecording material according to the invention is used as a printingplate.

In recent years, in plate-making and printing fields, automaticprocessors for printing plates have been widely used for rationalizationand standardization of plate-making works. This automatic processor canbe generally divided into a developing section and a post-treatingsection. The automatic processor generally comprises an apparatus fortransporting a printing plate, respective processing solution tanks, anda spraying unit, wherein each processing solution which is pumped up bya pump is sprayed from a spray nozzle while an exposed plating plate istransported horizontally. Recently, a method has been known in which aprinting plate is dipped and transported by in-liquid guide rolls in aprocessing solution tank which is filled with a processing solution. Insuch an automatic processing, a printing plate can be processed while areplenisher is supplied to each processing solution in accordance with aprocessed amount and an operating time. Alternatively, a so-calleddisposable processing system in which development is carried out with asubstantially unused processing solution can be employed.

In the invention, when there is an unnecessary image portion (forexample, a trace corresponding to a film edge of a original picturefilm) on a planographic printing plate which is obtained throughimage-wise exposure, development, washing with water and/or rinsingand/or gumming, the unnecessary image portion is erased. The unnecessaryimage portion is erased preferably by a method in which an erasingsolution is coated on the unnecessary image portion, allowed to standfor a predetermined time, then washed with water, as described in JP-BNo. 2-13293. Alternatively, the unnecessary portion may be erased by amethod as described in JP-A No. 59-174842 in which the unnecessary imageportion is irradiated with active rays propagated through an opticalfiber, followed by development.

Thus-obtained planographic printing plate may be used for printing afteroptionally coated with desensitizing gum. In order to improve a presslife of the planographic printing plate further, baking treatment iscarried out. If the planographic printing plate is subjected to thebaking, it is preferably subjected, in advance of the baking, to atreatment with a surface conditioner such as the surface conditionersdescribed in JP-B Nos. 61-2518, 55-28062, JP-A Nos. 62-31859 and61-159655.

When such a surface conditioner is used, the surface conditioner may beapplied to a surface of the planographic printing plate with a sponge orabsorbent cotton impregnated with the solution, or the printing platemay be dipped in a vat filled with the surface conditioner to be coatedwith the surface conditioner, or the surface conditioner may be appliedto a surface of the printing plate by an automatic coater. In order toobtain a better result, after the planographic printing plate is coatedwith a surface conditioner, a coated amount of the surface conditioneris preferably equalized with a squeegee or a squeegee roller.

Generally, the coating amount of the surface regulating solution mayadequately be from 0.03 to 0.8 g/m² (dry mass). The planographicprinting plate coated with the surface conditioner is, if necessary,heated to a high temperature by a baking processor (for example, BakingProcessor: “BP-1300”, commercially available from Fuji Photo Film Co.,Ltd.) after dried. A heating temperature in baking process is preferablyin the range of 180 to 300° C. A heating time in baking process ispreferably in the range of 1 to 20 minutes. However, suitable heatingtime and heating temperature vary based on type(s) of component(s) thatform(s) an image.

The planographic printing plate after the baking treatment may beoptionally subjected to conventional treatments such as washing withwater and gumming. However, when a surface conditioner containing awater-soluble polymer compound is used, a so-called desensitizingtreatment such as gumming may be omitted. The planographic printingplate obtained in this way is set in an offset printer and used formaking a large number of prints.

EXAMPLES

In the following, the present invention will be specifically explainedby using examples. However, the invention is by no means restricted tothe examples.

(Preparation of Substrate)

Combinations of the following processes were applied to 0.3 mm thickJIS-A-1050 aluminum plates, whereby substrates A, B, C and D wereprepared.

(a) Mechanical Surface Roughening

While a suspension of abrasive (siliceous sand) having a specificgravity of 1.12 in water was supplied to a surface of the aluminum plateas a polishing slurry, the surface of the aluminum plate wasmechanically roughened by using a rotating roller-like nylon brush. Theaverage particle diameter of the abrasive was 8 μm and the maximumparticle diameter thereof was 50 μm. Material of the nylon brush was6,10 nylon, a hair length was 50 mm, and a diameter of the hair was 0.3mm. A stainless steel barrel having a diameter of 300 mm was perforatedand nylon hairs were planted densely to prepare a nylon brush. Threerotary brushes were used. The distance between two supporting rollers(diameter: 200 mm) at the lower part of the brush was 300 mm. The brushrollers were pressed against the aluminum plate so that a load of adriving motor that drives the brushes exceeds the load before pressingthe brush rollers against the aluminum plate by 7 kW. The direction ofrotation of the brush was the same as the moving direction of thealuminum plate. The rotation number of the brushes was 200 rpm.

(b) Alkali Etching Treatment

The above-obtained aluminum plate was subjected to etching treatment bybeing sprayed with a 26% by mass aqueous solution of sodium hydroxide(containing aluminum ion at a concentration of 6.5% by mass) at 70° C.,whereby the aluminum plate was dissolved by 6 g/m². The plate was thenwashed with well water by being sprayed with well water.

(c) Desmutting Treatment

The aluminum plate was subjected to desmutting treatment by beingsprayed with a 1% by mass aqueous solution of nitric acid (containing0.5% by mass of aluminum ion) at 30° C., then the aluminum plate waswashed with water by being sprayed with water. The aqueous solution ofnitric acid used in the desmutting treatment was a waste solution of thefollowing process where the electrochemical surface roughening treatmentwas conducted with an alternating current in an aqueous solution ofnitric acid.

(d) Electrochemical Surface Roughening

Electrochemical surface roughening treatment was conducted continuouslyby using an alternating voltage of 60 Hz. The electrolytic solution wasan aqueous solution containing 10.5 g/liter of nitric acid and 5 g/literof aluminum ion. The temperature of the electrolytic solution was 50° C.The alternating current was a rectangler-wave alternating current havinga time TP, which is a time required for increase of the current from 0to the peak value, of 0.8 msec and the duty ratio of 1:1. A carbonelectrode was used as a counter electrode. Under these conditions, theelectrochemical surface roughening was carried out. Ferrite was used foran auxiliary anode. An electrolysis bath used was a radial-cell typeelectrolysis bath.

The peak electric current density was 30 A/dm², and a total quantity ofelectricity when the aluminum plate was the anode was 220° C./dm². 5% ofthe electric current from a power source was diverted to the auxiliaryanode.

The aluminum plate was then washed by being sprayed with water.

(e) Alkali Etching Treatment

The aluminum plate was subjected to etching treatment by being sprayedwith an aqueous solution comprising sodium hydroxide at a concentrationof 26% by mass and aluminum ion at a concentration of 6.5% by mass at32° C. to dissolve the aluminum plate by 0.20 g/m². By this etchingtreatment, a smut component, which was mainly consisting of an aluminumhydroxide formed during the electrochemical surface roughening treatmentwith an alternating voltage in the prior stage, was removed, and edgeportions of formed pits were dissolved to smooth the edge portions.Thereafter, the aluminum plate was washed by being sprayed with water.

(f) Desmutting Treatment

The aluminum plate was subjected to a desmutting treatment by beingsprayed with an aqueous solution containing 15% by mass nitric acid and4.5% by mass of aluminum ion at 30° C., and thereafter the aluminumplate was washed by being sprayed with water. The aqueous solution ofnitric acid used in the desmutting treatment was the waste solution ofthe electrochemical surface roughening treatment with an alternatingcurrent in an aqueous solution of nitric acid.

(g) Electrochemical Surface Roughening

Electrochemical surface roughening treatment was conducted continuouslyby using an alternating voltage of 60 Hz. The electrolytic solution wasan aqueous solution containing 7.5 g/liter of hydrochloric acid and 5g/liter of aluminum ion. The temperature of the electrolytic solutionwas 35° C. The alternating current was a rectangler-wave alternatingcurrent. A carbon electrode was used as a counter electrode. Under theseconditions, the electrochemical surface roughening was carried out.Ferrite was used for an auxiliary anode. An electrolysis bath used was aradial-cell type electrolysis bath.

The peak electric current density was 25 A/dm², and a total quantity ofelectricity when the aluminum plate was the anode was 50 C/dm².

The aluminum plate was then washed by being sprayed with water.

(h) Alkali Etching Treatment

The aluminum plate was subjected to etching treatment by being sprayedwith an aqueous solution comprising sodium hydroxide at a concentrationof 26% by mass and aluminum ion at a concentration of 6.5% by mass at32° C. to dissolve the aluminum plate by 0.10 g/m². By this etchingtreatment, a smut component, which was mainly consisting of an aluminumhydroxide formed during the electrochemical surface roughening treatmentwith an alternating voltage in the prior stage, was removed, and edgeportions of formed pits were dissolved to smooth the edge portions.Thereafter, the aluminum plate was washed by being sprayed with water.

(i) Desmutting Treatment

The aluminum plate was subjected to a desmutting treatment by beingsprayed with an aqueous solution containing 25% by mass of sulfuric acidand 0.5% by mass of aluminum ion at 60° C., then the aluminum plate waswashed by being sprayed with water.

(j) Anodic Oxidation Treatment

A sulfuric acid solution was used as the electrolytic solution. In everycase, the electrolytic solution contained 170 g/liter of sulfuric acidand 0.5% by mass of aluminum ion. The temperature of the electrolyticsolution was 43° C. The aluminum plate was then washed by being sprayedwith water.

The current density was about 30 A/dm² in every case. The final amountof the oxide film was 2.7 g/m².

(Substrate A)

Except that the etching amount in the (e) step was changed to 3.4 g/m²,the above steps (a) through (j) were carried out in the alphabeticalorder to prepare a substrate.

(Substrate B)

The above steps were carried out in the alphabetical order except thatthe steps (g), (h) and (i) were omitted, to prepare a substrate.

(Substrate C)

The above steps were carried out in the alphabetical order except thatthe steps (a), (g), (h) and (i) were omitted, to prepare a substrate.

(Substrate D)

The above steps were carried out in the alphabetical order except thatthe steps (a), (d), (e) and (f) were omitted and the total quantity ofelectricity in the step (g) was changed to 450 C/dm², to prepare asubstrate.

The substrates A, B, C and D were subsequently subjected to thefollowing hydrophilicity-imparting treatment and undercoating treatment.

(k) Alkali Metal Silicate Treatment

The aluminum substrate obtained by the anodic oxidation was immersed for10 seconds in a 1% by mass aqueous solution of sodium silicate No. 3 at30° C. in a bath. In this way, an alkali metal silicate treatment(silicate treatment) was conducted. Thereafter, the substrate was washedby being sprayed with water. The amount of adhered silicate was 3.6mg/m².

(Undercoating Treatment)

The aluminum substrate after the alkali metal silicate treatment wascoated with an undercoat solution having the following composition.Then, the aluminum substrate was dried for 15 seconds at 80° C. Acoating amount after drying was 16 mg/m². (Composition of undercoatsolution) The following polymer compound 0.3 g Methanol 100 g Water 1.0g

Weight average molecular weight 26,000

Examples 1 Through 8 and Comparative Examples 1 and 2

The obtained substrate A was coated with a first layer (lower layer)coating solution having the following composition by use of a wire barfollowed by drying at 150° C. for 60 seconds in a drying oven. Thecoating amount after drying was 0.85 g/m².

The obtained substrate having the lower layer was coated with a secondlayer (upper layer) coating solution having the following composition byuse of a wire bar followed by drying at 145° C. for 70 seconds in adrying oven. The total coating amount after drying was 1.15 g/m². Inthis way, positive planographic printing plate precursors of Examples 1through 8 and Comparative examples 1 and 2 were prepared.

(First Layer (Lower Layer) Coating Solution) Copolymer 1 2.133 g(synthesized according to the following) Cyanine dye A (the followingstructure) 0.098 g 2-mercapto-5-methylthio-1,3,4-thiadiazole 0.030 gCis-Δ⁴-tetrahydrophthalic anhydride 0.100 g 4,4′-sulfonyl diphenol 0.090g P-toluenesulfonic acid 0.008 g A compound obtained by converting acounter anion of Ethyl 0.100 g Violet to 6-hydroxynaphthalenesulfonicacid 3-methoxy-4-diazophenylamine hexafluorophosphate 0.030 gFluorine-type surfactant (MEGAFAC F-780 manufactured by 0.035 gDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone 26.6 g1-metoxy-2-propanol 13.6 g γ-butyrolactone 13.8 g Cyanine dye A

(Synthesis of Copolymer 1)

After agitation, into a 500 ml three-neck flask with a cooling jacketand a dropping funnel, 31.0 g (0.36 mole) of methacrylic acid, 39.1 g(0.36 mole) of ethyl chloroformate, and 200 ml of acetonitrile were put,and this mixture was agitated while cooled with an ice water bath. Tothis mixture, 36.4 g (0.36 mole) of triethylamine was added dropwise byusing a dropping funnel over about 1 hour. After completion of theaddition, the ice water bath was taken away, and the mixture wasagitated for 30 minutes at room temperature.

To the reaction mixture, 51.7 g (0.30 mole) of p-aminobenzenesulfonamidewas added, and the mixture was agitated for 1 hour while kept at 70° C.with an oil bath. After the reaction came to completion, the mixture wasadded to 1 liter of water while the water was agitated, and the obtainedmixture was agitated for 30 minutes. The mixture was filtrated and aprecipitate was separated. After 500 ml of water was added to theprecipitate to make a slurry, the slurry was filtrated, and the obtainedsolid was dried, whereby a white solid ofN-(p-aminosulfonylphenyl)methacrylamide was obtained (yield 46.9 g).

Subsequently, in a 20 ml three-neck flask with a stirrer, a coolingjacket and a dropping funnel, 4.61 g (0.0192 mole) ofN-(p-aminosulfonylphenyl)methacrylamide, 2.58 g (0.0258 mole) of ethylmethacrylate, 0.80 g (0.015 mole) of acrylonitrile and 20 g ofN,N-dimethyl acetamide were placed, and this mixture was agitated whilekept at 65° C. with a water bath. As a polymerization initiator, 0.15 gof 2,2′-azo bis(2,4-dimethyl valeronitrile) (product name: V-65,produced by Wako Pure Chemical Industries, Ltd.) was added to themixture, and the mixture was agitated under a nitrogen stream for 2hours while kept at 65° C. To the reaction mixture, a mixture of 4.61 gof the N-(p-aminosulfonylphenyl) methacrylamide, 2.58 g of methylmethacrylate, 0.80 g of acrylonitrile, 20 g of N,N-dimethyl acetamideand 0.15 g of “V-65” was further added dropwise over 2 hours by usingthe dropping funnel. After completion of the addition, the obtainedmixture was further agitated for 2 hours at 65° C. After the reactioncame to completion, 40 g of methanol was added to the mixture followedby cooling. The obtained mixture was added to 2 liter of water while thewater was agitated. After the mixture was agitated for 30 minutes, aprecipitate was separated by filtration and dried, whereby 15 g of awhite solid was obtained. The weight average molecular weight of thisparticular copolymer 1 was measured by gel permeation chromatography(polystyrene standard) and found to be 54,000. (Second layer (upperlayer) coating solution) Copolymer of ethyl methacrylate and2-methacryloyloxyethyl 0.030 g succinic acid (molar ratio 67:33, weightaverage molecular weight 92,000) Specific novolac resin (described inTable 18) 0.300 g Compound represented by the general formula (1-1)(ammonium 0.012 g compound described in Table 18) Cyanine dye A (theabove structure) 0.015 g Compound obtained by converting a counter anionof 0.012 g Ethyl Violet to 6-hydroxynaphthalenesulfonic acidFluorine-type surfactant (MEGAFAC F-780 manufactured 0.022 g byDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone  13.1 g1-metoxy-2-propanol  6.79 g(Evaluation of Planographic Printing Plate Precursor)

The planographic printing plate precursor was evaluated with respect todevelopment latitude, sensitivity, and storability after the exposure.The details of the evaluation method are as follows.

1. Development Latitude

A planographic printing plate precursor was preserved for 5 days under acondition of 25° C. and 50% r.h. Thereafter, the planographic printingplate precursor was image-wise exposed to test-pattern radiation byusing TRENDSETTER 3244 manufactured by Creo Corp with a beam intensityof 9.0 W and a drum revolution speed of 150 rpm.

A developer was prepared by changing a mass proportion of water in analkali developer having the following composition A or composition B sothat the dilution ratio of the developer and the electric conductivityof the developer was controlled. The developer was charged in a PSprocessor 900H manufactured by Fuji Photo Film Co., Ltd. Theplanographic printing plate precursor was developed by the PS processor900H at a liquid temperature of 30° C. for 22 seconds. The highestelectric conductivity and the lowest electric conductivity of thedevelopers by which the image portion was not dissolved and with whichexcellent development was carried out without causing contamination orcoloring due to remaining insufficiently developed photosensitive layerwere determined. The difference between the highest electricconductivity and the lowest electric conductivity was considered as thedevelopment latitude and used as a factor in the estimation.(Composition of alkali developer A) SiO₂•K₂O (K₂O/SiO₂ = 1/1 (molarratio)) 4.0% by mass Citric acid 0.5% by mass Polyethyleneglycol laurylether (weight average 0.5% by mass molecular weight 1,000) Water 95.0%by mass  (Composition of alkali developer B) D sorbit 2.5% by massSodium hydroxide 0.85% by mass  Polyethyleneglycol lauryl ether (weightaverage 0.5% by mass molecular weight 1,000) Water 96.15% by mass 2. Sensitivity

The planographic printing plate precursor was image-wise exposed to atest-pattern radiation having varying exposure energy by usingTRENDSETTER 3244 manufactured by Creo Corp.

Thereafter, the highest electric conductivity and the lowest electricconductivity of the developers by which the image portion was notdissolved and with which excellent development was carried out withoutcausing contamination or coloring due to remaining insufficientlydeveloped photosensitive layer were determined. The average of thehighest electric conductivity and the lowest electric conductivity wascalculated, and a developer having the average electric conductivity wasprepared. The minimum exposure amount (the minimum beam intensity at thedrum revolution speed of 150 rpm) that could develop a non-image portionwith this developer was measured and considered as sensitivity. Asmaller value refers to a higher sensitivity.

3. Storability after Exposure

After the exposed plate precursor was preserved in an environment of 25°C. and 70% r.h. for 1 hr, sensitivity was evaluated in a similar mannerto that in the above sensitivity evaluation. A degree of a decrease inthe sensitivity from immediately after the exposure was taken as anindex of storability after exposure. The storability value representsthe sensitivity 1 hr after the exposure, and a storability value whichis closer to the sensitivity immediately after the exposure was judgedas having better storability after exposure.

(Evaluation of Planographic Printing Plate Precursors According toExamples 1 Through 8 and Comparative Examples 1 and 2)

The respective planographic printing plate precursors according toExamples 1 through 8 and Comparative examples 1 and 2 were evaluatedwith respect to each of the development latitude, the sensitivity andthe storability after exposure, according to methods explained above.The developer B was used for development. The obtained results are shownin Table 18.

As shown in Table 18, it was confirmed that the planographic printingplate precursors of Examples 1 through 8, while maintaining thedevelopment latitude and the sensitivity, realized an improvement in thestorability after exposure. TABLE 18 Stora- bility Devel- Sensi- afteropment Novolac Ammonium tivity exposure lat- resin compound (W) (W)itude Example 1 P1 I-3  5.0 5.5 6 Example 2 P1 I-13 5.0 5.5 6 Example 3P1 I-37 5.0 5.5 6 Example 4 P1 II-3  5.0 5.5 6 Example 5 P2 I-3  4.8 5.26 Example 6 P2 I-13 4.8 5.2 6 Example 7 P2 I-37 4.8 5.2 6 Example 8 P2II-3  4.8 5.2 6 Comparative C1 I-3  6.0 8.0 6 example 1 Comparative P1 A6.0 6.5 2 example 2Novolac resin P1: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 30:30:40, weight average molecular weight =5500)Novolac resin P2: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 60:30:10, weight average molecular weight =4800)Novolac resin C1 Cresol-formaldehyde novolac (m-cresol:p-cresol = 6:4,weight average molecular weight = 5000)

The ammonium compound A (ammonium A) used in Comparative example 2 isshown below.

Examples 9 Through 16, Comparative Examples 3 and 4

On the obtained substrate C, a first layer (lower layer) coatingsolution having the following composition was coated by use of a wirebar followed by drying at 130° C. for 60 seconds in a drying oven. Thecoating amount after the drying in the oven was 0.60 g/m².

On the obtained substrate having the lower layer, a second layer (upperlayer) coating solution having the composition below was coated by useof a wire bar. After the coating, the substrate was dried at 150° C. for60 seconds in a drying oven. The total coating amount after the dryingin the oven was 1.25 g/m². Thereby, positive planographic printing plateprecursors of Examples 9 through 16 and Comparative examples 3 and 4were prepared. (First layer (lower layer) coating solution) Copolymer 12.133 g Cyanine dye A (above structure) 0.098 g2-mercapto-5-methylthio-1,3,4-thiadiazole 0.030 gCis-Δ⁴-tetrahydrophthalic anhydride 0.100 g 4,4′-sulfonyl diphenol 0.090g P-toluenesulfonic acid 0.008 g Compound obtained by converting acounter anion of Ethyl 0.100 g Violet to 6-hydroxynaphthalenesulfonicacid 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 gFluorine-type surfactant (MEGAFAC F-780 manufactured 0.035 g byDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone  26.6 g1-metoxy-2-propanol  13.6 g Dimethyl sulfoxide  13.8 g

(Second layer (upper layer) coating solution) Copolymer of ethylmethacrylate and 2-methacryloyloxyethyl 0.030 g succinic acid (molarratio 67:33, weight average molecular weight 92,000) Novolac resin(described in Table 19) 0.300 g Compound represented by the generalformula (1-1) (ammonium 0.016 g compound described in Table 19) Cyaninedye A (the above structure) 0.015 g Fluorine-type surfactant (MEGAFACF-780 manufactured 0.022 g by Dainippon Ink and Chemicals, Incorporated)Methyl ethyl ketone  13.1 g 1-metoxy-2-propanol  6.79 g(Evaluation of Examples 9 Through 16 and Comparative Examples 3 and 4)

The respective planographic printing plate precursors of Examples 9through 16 and Comparative examples 3 and 4 were evaluated in the samemanner as in Example 1. The developer B was used in the development. Theobtained results are shown in Table 19.

As shown in Table 19, it was found that samples of Examples, whilemaintaining the development latitude and the sensitivity, realized animprovement in the storability after exposure. TABLE 19 Stora- bilityDevel- Sensi- after opment Novolac Ammonium tivity exposure lat- resincompound (W) (W) itude Example 9 P3 I-2 5.5 5.75 8 Example 10 P3 I-9 5.55.75 8 Example 11 P3 II-7  5.5 5.75 8 Example 12 P3 IV-2   5.5 5.75 7Example 13 P4 I-2 5.0 5.5 8 Example 14 P4 I-9 5.0 5.5 8 Example 15 P4II-7  5.0 5.5 8 Example 16 P4 IV-2   5.0 5.5 7 Comparative C1 I-2 6.510.0 8 example 3 Comparative P3 A 6.0 6.5 3 example 4Novolac resin P3: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 40:40:20, weight average molecular weight =5200)Novolac resin P4: Phenol/xylenol-formaldehyde novolac(phenol:2,5-xylenol = 70:30, weight average molecular weight = 4600)Novolac resin C1: Cresol-formaldehyde novolac (m-cresol:p-cresol = 6:4,weight average molecular weight = 5000)

The ammonium compound A (ammonium A) used in Comparative example 4 isthe same as that used in Comparative example 2.

Examples 17 Through 24, Comparative Examples 5 and 6

On the obtained substrate D, a first layer (lower layer) coatingsolution having the following composition was coated by use of a wirebar followed by drying at 150° C. for 60 seconds in a drying oven. Thecoating amount after the drying was 0.81 g/m².

On the obtained substrate having the lower layer, a second layer (upperlayer) coating solution having the composition below was coated by useof a wire bar. After the coating, the substrate was dried at 150° C. for60 seconds in a drying oven. The total coating amount after the dryingwas 0.99 g/m². In this way, positive planographic printing plateprecursors of Examples 17 through 24 and Comparative examples 5 and 6were prepared. (First layer (lower layer) coating solution) Copolymer 1mentioned above 2.133 g Cyanine dye A (above structure) 0.098 gCis-Δ⁴-tetrahydrophthalic anhydride 0.110 g 4,4′-sulfonyl diphenol 0.090g P-toluenesulfonic acid 0.008 g Compound obtained by converting acounter anion of Ethyl 0.100 g Violet to 6-hydroxynaphthalenesulfonicacid 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 gFluorine-type surfactant (MEGAFAC F-780 manufactured by 0.035 gDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone  26.6 g1-metoxy-2-propanol  13.6 g γ-butyrolactone  13.8 g

(Second layer (upper layer) coating solution) Copolymer of ethylmethacrylate and 2-methacryloyloxyethyl 0.030 g succinic acid (molarratio 67:33, weight average molecular weight 92,000) Novolac resin(Table 20) 0.300 g Compound represented by the general formula (1-1)(ammonium 0.020 g compound described in Table 20) Cyanine dye A (abovestructure) 0.015 g Fluorine-type surfactant (MEGAFAC F-780 manufactured0.022 g by Dainippon Ink and Chemicals, Incorporated) Methyl ethylketone  13.1 g 1-metoxy-2-propanol  6.79 g(Evaluation of Examples 17 Through 24 and Comparative Examples 5 and 6)

The respective planographic printing plate precursors obtained abovewere evaluated according to the above-mentioned methods. The developer Awas used in the development. The obtained results are shown in Table 20.

As shown in Table 20, it was found that the planographic printing plateprecursors of Examples 17 through 24, while maintaining the developmentlatitude and the sensitivity, realized an improvement in the storabilityafter exposure. TABLE 20 Stora- bility Devel- Sensi- after opmentNovolac Ammonium tivity exposure lat- resin compound (W) (W) itudeExample 17 P5 I-2 6.0 7.0 8 Example 18 P5 I-9 6.0 7.0 8 Example 19 P5II-7  6.0 7.0 8 Example 20 P5 IV-2   6.0 7.0 7 Example 21 P6 I-2 6.0 7.08 Example 22 P6 I-9 6.0 7.0 8 Example 23 P6 II-7  6.0 7.0 8 Example 24P6 IV-2   6.0 7.0 7 Comparative C2 I-2 7.0 12.0 7 example 5 ComparativeP5 B 6.5 8.0 2 example 6Novolac resin P5: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 40:40:20, weight average molecular weight =8000)Novolac resin P6: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 60:30:10, weight average molecular weight =7700)Novolac resin C2: Cresol-formaldehyde novolac (m-cresol:p-cresol = 7:3,weight average molecular weight = 10000)

The ammonium compound B (ammonium B) used in Comparative example 6 isshown below.

Examples 25 Through 32, Comparative Examples 7 and 8

On the obtained substrate D, the following image forming layer coatingsolution was coated and dried at 150° C. for 1 minute to form an imageforming layer, whereby planographic printing plate precursors ofExamples 25 through 32 and Comparative examples 7 and 8 were obtained.The coating amounts after the drying were 1.55 g/m². (Image forminglayer coating solution) Novolac resin (described in Table 21)  1.0 gCompound represented by the general formula (1-1) (ammonium 0.05 gcompound described in Table 21) Cyanine dye A (above structure) 0.05 gDye obtained by converting a counter anion of Victoria Pure 0.01 g BlueBOH to 1-naphthalenesulfonic acid anion Fluorine-type surfactant(MEGAFAC F-177 manufactured 0.05 g by Dainippon Ink and Chemicals,Incorporated) Methyl ethyl ketone  9.0 g 1-metoxy-2-propanol  9.0 g(Evaluation of Examples 25 Through 32 and Comparative Examples 7 and 8)

The respective planographic printing plate precursors of Examples 25through 32 and Comparative examples 7 and 8 were evaluated in the samemanner as in Example 1. The developer A was used in the development. Theobtained results are shown in Table 21.

As shown in Table 21, it was found that the planographic printing plateprecursors of Examples 25 through 32, while maintaining the developmentlatitude and the sensitivity, realized an improvement in the storabilityafter exposure. TABLE 21 Stora- bility Devel- Sensi- after opmentNovolac Ammonium tivity exposure lat- resin compound (W) (W) itudeExample 25 P7 I-2 4.0 4.5 5 Example 26 P7 I-9 4.0 4.5 6 Example 27 P7II-7  4.0 4.5 5 Example 28 P7 IV-2   4.0 4.5 5 Example 29 P8 I-2 4.0 4.56 Example 30 P8 I-9 4.0 4.5 6 Example 31 P8 II-7  4.0 4.5 6 Example 32P8 IV-2   4.0 4.5 6 Comparative C2 I-2 5.5 8.0 5 example 7 ComparativeP7 B 4.5 5.5 1 example 8Novolac resin P7: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 20:60:20, weight average molecular weight =10200)Novolac resin P8: Phenol/xylenol-formaldehyde novolac (phenol:2,5xylenol = 60:40, weight average molecular weight = 11000)Novolac resin C2: Cresol-formaldehyde novolac (m-cresol:p-cresol = 7:3,weight average molecular weight = 10000)

The ammonium compound B (ammonium B) used in Comparative example 8 isthe same as that used in Comparative example 6.

Examples 33 Through 40, Comparative Examples 9 and 10

On the substrate A, a first layer (lower layer) coating solution havingthe following composition was coated by use of a wire bar followed bydrying at 150° C. for 60 seconds in a drying oven. The coating amountafter the drying was 0.85 g/m².

On the obtained substrate with the lower layer, a second layer (upperlayer) coating solution having the composition below was coated by useof a wire bar. After the coating, the substrate was dried in a dryingoven at 140° C. for 60 seconds. The total coating amount was 1.17 g/m².In this way, positive planographic printing plate precursors accordingto Examples 33 through 40 and Comparative examples 9 and 10 wereprepared. (First layer (lower layer) coating solution) Copolymer 1 inExample 1 2.133 g Cyanine dye B (the following structure) 0.098 g2-mercapto-5-methylthio-1,3,4-thiadiazole 0.030 gCis-Δ⁴-tetrahydrophthalic anhydride 0.100 g 4,4′-sulfonyl diphenol 0.090g P-toluenesulfonic acid 0.008 g Compound obtained by converting acounter anion of Ethyl 0.100 g Violet to 6-hydroxynaphthalenesulfonicacid 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 gFluorine-type surfactant (MEGAFAC F-780 manufactured by 0.035 gDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone  26.6 g1-metoxy-2-propanol  13.6 g γ-butyrolactone  13.8 g Cyanine Dye B

(Second layer (upper layer) coating solution) Copolymer of ethylmethacrylate and 2-methacryloyloxyethyl 0.030 g succinic acid (molarratio 67:33, weight average molecular weight 92,000) Particular novolacresin (described in Table 22) 0.300 g Onium salt represented by thegeneral formula (1-2) (onium 0.012 g salt described in Table 22) Cyaninedye B mentioned above 0.015 g Compound obtained by converting a counteranion of Ethyl 0.012 g Violet to 6-hydroxynaphthalenesulfonic acidFluorine-type surfactant (MEGAFAC F-780 manufactured 0.022 g byDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone  13.1 g1-metoxy-2-propanol  6.79 g(Evaluation of Planographic Printing Plate Precursor)

The planographic printing plate precursors were evaluated with respectto each of the development latitude, sensitivity and storability afterexposure. Details of evaluation methods are as shown below.

1. Development Latitude

A planographic printing plate precursor was preserved for 5 days underthe condition of 25° C. and 50% r.h. Thereafter, the planographicprinting plate was image-wise exposed to a test pattern radiation byusing a TRENDSETTER 3244 manufactured by Creo Corp with a beam intensityof 9.0 W and a drum revolution speed of 150 rpm.

A developer was prepared by changing a mass proportion of water in analkali developer having the composition A or composition B recited inExample 1 so that the dilution ratio of the developer and the electricconductivity of the developer was controlled. The developer was chargedin a PS processor 900H manufactured by Fuji Photo Film Co., Ltd. Theplanographic printing plate precursor was developed by the PS processor900H at a liquid temperature of 29° C. for 24 seconds. The highestelectric conductivity and the lowest electric conductivity of thedevelopers by which the image portion was not dissolved and with whichexcellent development was carried out without causing contamination orcoloring due to remaining insufficiently developed photosensitive layerwere determined. The difference between the highest electricconductivity and the lowest electric conductivity was considered as thedevelopment latitude and used as a factor in the estimation.

2. Sensitivity

The sensitivity was measured in the same manner as in Example 1.

3. Storability after Exposure

The storability after exposure was measured in the same manner as inExample 1.

(Evaluation of Planographic Printing Plate Precursors of Examples 33Through 40 and Comparative Examples 9 and 10)

The respective planographic printing plate precursors of Examples 33through 40 and Comparative examples 9 and 10 were evaluated with respectto each of the development latitude, sensitivity and storability afterexposure according to the above-mentioned methods. The developer B wasused in the development. The obtained results are shown in Table 22.

As shown in Table 22, it was found that the planographic printing plateprecursors of Examples 33 through 40, while maintaining the developmentlatitude and the sensitivity, realized an improvement in the storabilityafter exposure. TABLE 22 Stora- bility Devel- Sensi- after opmentNovolac tivity exposure lat- resin Onium salt (W) (W) itude Example 33P1 C-1 5.0 5.2 6 Example 34 P1 C-3 5.0 5.2 6 Example 35 P1 C-4 5.0 5.2 6Example 36 P1  C-10 5.0 5.0 6 Example 37 P2 C-1 4.8 5.0 6 Example 38 P2C-3 4.8 5.0 6 Example 39 P2 C-4 4.8 5.0 6 Example 40 P2  C-10 4.8 4.8 6Comparative CP1 C-1 6.0 7.0 6 example 9 Comparative P1 A 6.0 6.5 2example 10Novolac resin P1: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 30:40:30, weight average molecular weight =5000)Novolac resin P2: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 60:30:10, weight average molecular weight =5200)Novolac resin CP1: Cresol-formaldehyde novolac (m-cresol:p-cresol = 6:4,weight average molecular weight = 5000)

The onium salt A used in Comparative example 10 is the same as theammonium compound used in Comparative example 2.

Examples 41 Through 48, Comparative Examples 11 and 12

On the substrate C, a first layer (lower layer) coating solution havingthe following composition was coated by use of a wire bar followed bydrying at 130° C. for 60 seconds in a drying oven. The coating amountafter the drying was 0.60 g/m².

On the obtained substrate with the lower layer, a second layer (upperlayer) coating solution having the composition below was coated by useof a wire bar. After the coating, the substrate was dried in a dryingoven at 150° C. for 60 seconds. The total coating amount after thedrying was 1.25 g/m². In this way, positive planographic printing plateprecursors of Examples 41 through 48 and Comparative examples 11 and 12were prepared. (First layer (lower layer) coating solution) Copolymer 1in Example 1 2.133 g Cyanine dye C (following structure) 0.098 g2-mercapto-5-methylthio-1, 3, 4-thiadiazole 0.030 gCis-Δ⁴-tetrahydrophthalic anhydride 0.100 g 4, 4′-sulfonyl diphenol0.090 g P-toluenesulfonic acid 0.008 g Compound obtained by converting acounter anion 0.100 g of Ethyl Violet to 6-hydroxynaphthalenesulfonicacid 3-methoxy-4-diazodiphenylamine hexafluorophosphate 0.030 gFluorine-type surfactant (MEGAFAC F-780 manufactured 0.035 g byDainippon Ink and Chemicals, Incorporated) Methyl ethyl ketone  26.6 g1-metoxy-2-propanol  13.6 g Dimethyl sulfoxide  13.8 g

(Second layer (upper layer) coating solution) Copolymer of ethylmethacrylate and 2-methacryloyloxyethyl 0.030 g succinic acid (molarratio 67:33, weight average molecular weight 92,000) Novolac resin(described in Table 23) 0.300 g Onium salt represented by the generalformula (1-2) (onium 0.016 g salt described in Table 23) Cyanine dye Cshown above 0.015 g Fluorine-type surfactant (MEGAFAC F-780 manufactured0.022 g by Dainippon Ink and Chemicals, Incorporated) Methyl ethylketone  13.1 g 1-metoxy-2-propanol  6.79 g(Evaluation of Examples 41 Through 48 and Comparative Examples 11 and12)

The respective planographic printing plate precursors of Examples 41through 48 and Comparative examples 11 and 12 were evaluated in the samemanner as in Example 33. The developer B was used in the development.The obtained results are shown in Table 23.

As shown in Table 23, it was found that samples of Examples, whilemaintaining the development latitude and the sensitivity, realized animprovement in the storability after exposure. TABLE 23 Stora- bilityDevel- Sensi- after opment Novolac tivity exposure lat- resin Onium salt(W) (W) itude Example 41 P3 C-2 5.5 5.8 8 Example 42 P3 C-8 5.5 5.8 8Example 43 P3  C-16 5.5 5.8 8 Example 44 P3  C-20 5.5 5.6 7 Example 45P4 C-2 5.0 5.3 8 Example 46 P4 C-8 5.0 5.3 8 Example 47 P4  C-16 5.0 5.38 Example 48 P4  C-20 5.0 5.0 8 Comparative CP1 C-1 6.5 7.5 8 example 11Comparative P3 A 6.0 7.0 3 example 12Novolac resin P3: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 40:40:20, weight average molecular weight =5200)Novolac resin P4: Phenol/xylenol-formaldehyde novolac(phenol:2,5-xylenol = 70:30, weight average molecular weight = 4600)Novolac resin CP1: Cresol-formaldehyde novolac (m-cresol:p-cresol = 6:4,weight average molecular weight = 5000)

The onium salt A (ammonium A) used in Comparative example 12 is the sameas that used in Comparative example 10.

Examples 49 Through 56, Comparative Examples 13 and 14

On the obtained substrate D, a first layer (lower layer) coatingsolution having the following composition was coated by use of a wirebar followed by drying at 150° C. for 60 seconds in a drying oven. Thecoating amount after the drying was 0.81 g/m².

On the obtained substrate with the lower layer, a second layer (upperlayer) coating solution having the composition below was coated by useof a wire bar. After the coating, the substrate was dried in a dryingoven at 150° C. for 60 seconds. The total coating amount after thedrying was 0.99 g/m². In this way, positive planographic printing plateprecursors according to Examples 49 through 56 and Comparative examples13 and 14 were prepared. (First layer (lower layer) coating solution)Copolymer 1 in Example 1 2.133 g Cyanine dye D (following structure)0.098 g Cis-Δ⁴-tetrahydrophthalic anhydride 0.110 g 4, 4'-sulfonyldiphenol 0.090 g P-toluenesulfonic acid 0.008 g Compound obtained byconverting a counter anion of 0.100 g Ethyl Violet to6-hydroxynaphthalenesulfonic acid 3-methoxy-4-diazodiphenylaminehexafluorophosphate 0.030 g Fluorine-type surfactant (MEGAFAC F-780manufactured 0.035 g by Dainippon Ink and Chemicals, Incorporated)Methyl ethyl ketone  26.6 g 1-metoxy-2-propanol  13.6 g γ-butyrolactone 13.8 g

(Second layer (upper layer) coating solution) Copolymer of ethylmethacrylate and 2-methacryloyloxyethyl 0.030 g succinic acid (molarratio 67:33, weight average molecular weight 92,000) Novolac resin(described in Table 24) 0.300 g Onium salt represented by the generalformula (1-2) (onium 0.020 g salt described in Table 24) Cyanine dye Dmentioned above 0.015 g Fluorine-type surfactant (Megafac F-780manufactured 0.022 g by Dainippon Ink and Chemicals, Incorporated)Methyl ethyl ketone  13.1 g 1-metoxy-2-propanol  6.79 g(Evaluation of Examples 49 Through 56 and Comparative Examples 13 and14)

The obtained respective planographic printing plate precursors wereevaluated in the same manner as in Example 33. The developer A was usedin the development. The obtained results are shown in Table 24.

As shown in Table 24, it was found that the planographic printing plateprecursors of Examples 49 through 56, while maintaining the developmentlatitude and the sensitivity, realized an improvement in the storabilityafter exposure. TABLE 24 Stora- bility Devel- Sensi- after opmentNovolac tivity exposure lat- resin Onium salt (W) (W) itude Example 49P5 C-4  6.0 6.3 8 Example 50 P5 C-13 6.0 6.3 8 Example 51 P5 C-21 6.06.2 8 Example 52 P5 C-28 6.0 6.2 7 Example 53 P6 C-4  6.0 6.4 8 Example54 P6 C-13 6.0 6.4 8 Example 55 P6 C-21 6.0 6.1 8 Example 56 P6 C-28 6.06.2 7 Comparative CP2 C-4  7.0 8.0 7 example 13 Comparative P5 B 6.5 8.02 example 14Novolac resin P5: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 40:40:20, weight average molecular weight =8000)Novolac resin P6: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 60:30:10, weight average molecular weight =7700)Novolac resin CP2: Cresol-formaldehyde novolac (m-cresol:p-cresol = 7:3,weight average molecular weight = 10000)

The onium salt B used in Comparative example 14 was the same as theammonium compound B used in Comparative example 6.

Examples 57 Through 64, Comparative Examples 15 and 16

On the obtained substrate D, the following image forming layer coatingsolution was coated followed by drying at 150° C. for 1 minute, to forman image forming layer. Thereby, planographic printing plate precursorsof Examples 57 through 64 and Comparative examples 15 and 16 wereobtained. The coating amount after the drying was 1.55 g/m². (Imageforming layer coating solution) Novolac resin (described in Table 25) 1.0 g Onium salt represented by the general formula (1-2) 0.05 g (oniumsalt described in Table 25) Cyanine dye D mentioned above 0.05 g Dyeobtained by converting a counter anion of Victoria 0.01 g Pure Blue BOHto 1-naphthalenesulfonic acid anion Fluorine-type surfactant (MEGAFACF-177 manufactured by 0.05 g Dainippon Ink and Chemicals, Incorporated)Methyl ethyl ketone  9.0 g 1-metoxy-2-propanol  9.0 g(Evaluation of Examples 57 Through 64 and Comparative Examples 15 and16)

The respective planographic printing plate precursors of Examples 57through 64 and Comparative examples 15 and 16 were evaluated in the samemanner as in Example 33. The developer A was used in the development.The obtained results are shown in Table 25.

As shown in Table 25, it was found that the planographic printing plateprecursors of Examples 57 through 64, while maintaining the developmentlatitude and the sensitivity, realized an improvement in the storabilityafter exposure. TABLE 25 Stora- bility Devel- Sensi- after opmentNovolac tivity exposure lat- resin Onium salt (W) (W) itude Example 57P7 C-14 4.0 4.0 5 Example 58 P7 C-22 4.0 4.3 6 Example 59 P7 C-23 4.04.4 5 Example 60 P7 C-29 4.0 4.3 5 Example 61 P8 C-14 3.8 3.9 6 Example62 P8 C-22 3.8 4.1 6 Example 63 P8 C-23 3.8 4.1 6 Example 64 P8 C-29 3.84.0 6 Comparative CP2 C-1  5.5 6.5 5 example 15 Comparative P7 B 4.5 5.51 example 16Novolac resin P7: Phenol/cresol-formaldehyde novolac(phenol:m-cresol:p-cresol = 20:60:20, weight average molecular weight =10200)Novolac resin P8: Phenol/xylenol-formaldehyde novolac(phenol:2,5-xylenol = 60:40, weight average molecular weight = 11000)Novolac resin CP2: Cresol-formaldehyde novolac (m-cresol:p-cresol = 7:3,weight average molecular weight = 10000)

The onium salt B (ammonium B) used in Comparative example 16 was thesame as that used in Comparative example 14.

According to the invention, an image forming material that is useful forthe heat-mode type positive planographic printing plate precursor andexcellent in solubility discrimination and in the storability afterexposure can be provided. A planographic printing plate precursorutilizing the image forming material can improve storability afterexposure without deteriorating development latitude and sensitivity.

1. An image forming material comprising, on a substrate, an imageforming layer which includes at least (A) a novolac type phenolic resincontaining phenol as a structural unit, (B) a photo-thermal convertingagent, and (C) a compound represented by the following formula (1-1):

wherein in formula (1-1), R¹ represents a residue which, together withN¹, forms a ring structure; R² and R³ each independently represent anorganic group and may combine with each other to form a ring structure;at least one of R² and R³ may combine with R¹ to form a ring structure;and X⁻ represents a conjugate base of an organic acid or an inorganicacid.
 2. The image forming material according to claim 1, wherein thecompound represented by formula (1-1) is represented by the followingformula (1-1-a):

wherein in formula (1-1-a), R² and R³ each independently represent anorganic group and may combine with each other to form a ring structure;X⁻ represents a conjugate base of an organic acid or an inorganic acid;R⁴ through R⁷ each independently represent a hydrogen atom or asubstituent, may be the same as or different from one another, and maycombine with one another to form a ring; R⁴ through R⁷ may each combinewith L¹, R² or R³ to form a ring structure; when a bond between L¹ andC¹ or C² is a double bond or a triple bond, some of R⁴ through R⁷do/does not exist in accordance with the existence of the double bond orthe triple bond; L¹ represents a single bond or a divalent linkage groupwhich, together with —C¹—N¹—C², forms a ring structure; R⁴ and R⁵ mayrepresent an identical atom or an identical substituent so that a bondbetween C¹ and R⁴, which is also R⁵, becomes a double bond; and R⁶ andR⁷ may represent an identical atom or an identical substituent so that abond between C² and R⁶, which is also R⁷, becomes a double bond.
 3. Theimage forming material according to claim 1, wherein a mass of thecompound represented by formula (1-1) is 50% or less of a mass of atotal solids content in the image forming layer.
 4. The image formingmaterial according to claim 1, wherein the novolac type phenolic resinis a resin obtained by condensing phenol, a substituted phenolrepresented by the following formula (I), and an aldehyde:

wherein in formula (I), R¹ and R² each independently represent ahydrogen atom, an alkyl group, or a halogen atom.
 5. The image formingmaterial according to claim 4, wherein a phenol content in monomers thatconstitute the novolac type phenolic resin is from 21 to 90% by mole. 6.The image forming material according to claim 4, wherein a weightaverage molecular weight of the novolac type phenolic resin is from 500to
 50000. 7. The image forming material according to claim 4, wherein aproportion of the novolac type phenolic resin to a total solids contentin the image forming layer is from 0.1 to 20% by mass.
 8. An imageforming material comprising, on a substrate, an image forming layerwhich includes at least (A) a novolac type phenolic resin containingphenol as a structural unit, (B) a photo-thermal converting agent, and(C) an onium salt represented by the following formula (1-2):X⁻M⁺  Formula (1-2) wherein, in formula (1-2), X⁻ represents an anionincluding at least one substituent that has an alkali dissociativeproton and M⁺ is represented by the following formula (M-I)

wherein in formula (M-1), R¹ represents a residue which, together withN¹, forms a ring structure; R² and R³ each independently represent anorganic group and may combine with each other to form a ring structure;and at least one of R² and R³ may combine with R¹ to form a ringstructure.